Showing every level. Pick a course and the topics it is not examined on are hidden.
Community College of Allegheny County · Nursing
Dosage calculation
Every topic on the CCAC Drug Dosage Calculation Blueprint, labelled by the course level that examines it. Each exam is 25 questions and the pass mark is 92% — 23 of 25, two attempts, and no medication administration in clinical until you pass.
Companion paper: the practice exam, 182 questions with worked answers, which builds a 25-question paper to any level's blueprint.
- 00 · How you are tested
- 01 · Notation, labels and reading a vial
- 02 · Conversions to memorise
- 03 · The three methods
- 04 · Intake and output
- 05 · Oral medications
- 06 · SubQ, IM and IV push
- 07 · Reconstitution
- 08 · Insulin
- 09 · IV flow rates
- 10 · Complex two-step problems
- 11 · Heparin
- 12 · Titrated drips
- 13 · Equipment: cups, syringes and cartridges
- 14 · Formula sheet
- 15 · Beyond the blueprint
Section 00
How you are tested
Every dosage exam in the program is 25 questions and the pass mark is 92% — 23 of 25. You get two attempts. Fail the second and you fail the nursing course the exam belongs to, and until you pass you may not give medications in clinical. Calculators are permitted.
Which courses have a dosage exam
NUR 110, NUR 130, NUR 220, NUR 230 and NUR 240. Not NUR 120. In NUR 110 the exam is given alongside the drug-administration material; in the later courses it comes no later than the first week of the semester. Students taking NUR 220 and NUR 230 consecutively sit one exam in the first week, and the Boyce Fast Track timeline may be accelerated.
The retest window is a duration, not a date. In NUR 110 the successful retest must be completed within two weeks of the first attempt. In NUR 130, 220, 230 and 240 it must be completed by the end of the second week of the semester. Only one retake is permitted.
Being unable to administer medications correctly in the clinical setting — dosage calculation included — automatically constitutes an Unsafe Performance. And a student who is unsuccessful in clinical before the dosage exam is not permitted to sit it.
Most lost points are not lost on arithmetic. They are lost on labels, zeros and rounding, which is why those rules come before any formula.
An unlabelled answer is marked wrong even when the number is right. Write 2 tablets, 1.5 mL, 6 units, 31 gtt/min. Where the question asks per dose, say per dose.
Doses below one get a leading zero: 0.5 mL, not .5 mL. Never add a trailing zero: 0.5 mL, not 0.50 mL. A missed decimal point is a tenfold error and this notation is what prevents it.
Rule 3 · Rounding, and the syringe you are using
| If the volume is… | Calculate to… | Round to… | Example |
|---|---|---|---|
| Greater than 1 mL | Hundredths | Nearest tenth | 1.25 → 1.3 mL 1.24 → 1.2 mL |
| Less than 1 mL | Thousandths | Nearest hundredth | 0.969 → 0.97 mL 0.963 → 0.96 mL |
The program states a second rule alongside it, about the delivery device:
- A 1 mL tuberculin syringe is the finest device: CCAC's rule is to calculate to the thousandths and round to the hundredth, which is the place its barrel is graduated in.
- 3 mL, 5 mL and 10 mL syringes are calculated to the nearest hundredth as well — but read what the barrel offers: a 3 mL syringe is marked in tenths, and 5 and 10 mL syringes in fifths, one line every 0.2 mL.
Note the answer you write and the precision you can draw are two different questions. The volume rule decides what goes on the page; the syringe rule decides what you can measure — so read the dose and the device before you round.
The tenths-and-hundredths rule above is for volumes in millilitres. Everything else has its own rule:
- gtt/min → whole number. You cannot give part of a drop.
- mL/hr → whole number on the exam; titration pumps accept tenths.
- Tablets → whole or half, and only a scored tablet may be halved.
- Capsules → whole only.
- Insulin → whole units on a U-100 syringe.
- Kilograms → nearest tenth, and this is the one value rounded before the dose math.
- Ounces, teaspoons and other non-millilitre answers → CCAC's written rounding rules cover millilitres only. Its answer key writes 200 mL ÷ 30 = 6.67 oz (or 6 2/3 oz) — one exact value written two ways — while most textbooks would answer 6.7 oz. On a CCAC paper, write it the way the key writes it; both forms satisfy every rule the program actually states.
Aim for at least two significant digits where the arithmetic produced them — the program's own rule of thumb, meant to stop you reporting a bare 7 when the calculation gave 7.4. It is not licence to pad a zero: 0.5 mL never becomes 0.50 mL, because Rule 2 outranks it. And when a digit falls exactly on a half, round up — 1.25 becomes 1.3.
Any answer naming a clock time is four-digit 24-hour time, no colon, no AM or PM: 0730, 1415, 2200.
Carry full decimals through every intermediate step and round only the final answer — with one exception: convert pounds to kilograms and round that to the nearest tenth first, then use the rounded weight in every later step. Double-rounding bites hardest on weight-based drips, where a tenth of a kilogram moves the rate.
What is on each exam
The blueprint publishes the question count per topic. The distribution is where your study time should go.
| Topic | NUR 110 | NUR 130 | 220 / 230 / 240 |
|---|---|---|---|
| Household measures & converting between systems | 5 | 2 | 2 |
| Metric conversions, including pounds to kilograms | 3 | 2 | 2 |
| Intake and output | 2 | 1 | 1 |
| Oral medications | 6 | 3 | 3 |
| Parenteral — SubQ / IM, and IV push from 220 | 5 | 3 | 3 |
| Reconstitution | 2 | 2 | 1 |
| Insulin — sliding scale, mixing, drips from 220 | 2 | 2 | 3 |
| IV flow rates — primary and secondary | — | 5 | 5 |
| Complex two-step problems | — | 5 | — |
| Heparin bolus (weight-based) and infusion | — | — | 4 |
| Medication titration | — | — | 1 |
| Total | 25 | 25 | 25 |
Two-step work has no row of its own at NUR 220/230/240 — there it is folded into the oral and parenteral rows, which read “1 step or 2 step method”.
Two things stand out. Conversions and oral doses are 14 of the 25 questions on the NUR 110 exam — over half of it, and at 92% you can miss only two, so they have to be automatic. From NUR 220 onward, IV rates and heparin together are nine of twenty-five.
Everything is shown by default. Pick a course level in the bar at the top and the sections that level is not examined on disappear, along with the level-specific notes inside other sections — IV push, reconstitute-then-infuse, and the insulin drip worked example are all NUR 220 and above. The topic labels stay visible, so you can always see which level a concept belongs to.
Section 01
Notation, labels and reading a vial
The mechanical rules, in the form the exam applies them.
Reading a label
A label states a concentration, not a dose. 80 mg per 2 mL means 40 mg in every millilitre; it does not mean you give 2 mL. Reduce every label to a per-millilitre figure before you calculate and the commonest error in dosage work disappears.
Worked example
Order: Lasix 40 mg I.V. Available: Lasix 100 mg per 10 mL.
- Per-millilitre strength: 100 mg ÷ 10 mL = 10 mg/mL.
- Volume: 40 ÷ 10 = 4 mL.
FINAL ANSWER: 4 mL
Reading 100 mg as the dose would have you draw the whole vial.
Matching units before you calculate
Milliequivalents measure chemical combining power rather than mass, so mEq and mg are not interchangeable figures you can convert in your head — the conversion depends on the salt and its valence. On the exam this never comes up as a conversion, because an mEq order is always paired with an mEq-labelled stock (KCl 20 mEq per 15 mL). Match unit to unit; if an order and a label genuinely disagree in kind, that is a pharmacy question.
Write units in full: a handwritten U reads as 0 or 4, turning 12U into 120. q.o.d. is misread as daily — write every other day. Both are on the ISMP list of error-prone abbreviations, and both are reasons an order should be clarified before it is given.
The abbreviations the orders use
The exam writes orders the way the units do. These are the ones worth knowing cold.
| Abbreviation | Meaning | Abbreviation | Meaning |
|---|---|---|---|
| q.d. | every day | a.c. | before meals |
| b.i.d. | twice a day | p.c. | after meals |
| t.i.d. | three times a day | h.s. | at bedtime (hour of sleep) |
| q.i.d. | four times a day | q.h.s. | every bedtime |
| q.h | every hour | p.r.n. | as needed |
| q.2.h / q.4.h | every 2 / 4 hours | stat | immediately |
| q.a.m. | every morning | ad lib | as desired |
| p.o. | by mouth | q.s. | as much as required |
| S.C. / subcut | subcutaneous | I.M. / I.V. | intramuscular / intravenous |
q.o.d. (every other day) appears on older orders and is discouraged — write it out. Note that q.i.d. is four times a day and q.4.h is every four hours: six doses, not four, and they are not the same order.
Abbreviations that appear inside the order itself
IV stems are written in shorthand, and the shorthand is part of the question.
| Written | Means | Written | Means |
|---|---|---|---|
| D5W | 5% dextrose in water | NS | normal saline, 0.9% |
| D5NS | 5% dextrose in normal saline | 1/2 NS | 0.45% saline |
| D5 1/2 NS | 5% dextrose in 0.45% saline | LR or RL | lactated Ringer's |
| D10W | 10% dextrose in water | KCl 20 mEq/L | potassium added to the bag |
The number is always the percent strength, and percent means grams per 100 mL — so a litre of D5W carries 50 g of dextrose.
Write "units" in full, in lower case, after the number, with a space: 2000 units, 45,000 units. Use a comma once a quantity reaches five digits. Leave a space between the number and its abbreviation — 0.5 mL, not 0.5mL — and write fractional amounts as decimals, so 0.5 mL rather than 1/2 mL. These are the labelling rules an answer is marked against, not style preferences.
Section 02
Conversions to memorise
On the exam: NUR 110 8 · NUR 130 4 · 220/230/240 4
Two blueprint rows, and together the largest block on the NUR 110 exam: five questions on household measures and converting between systems, three on metric and weight. Nothing else in this guide works until these are automatic.
| Metric | Household & weight | Time & other |
|---|---|---|
| 1 g = 1000 mg | 1 kg = 2.2 lb | 1 hr = 60 min |
| 1 mg = 1000 mcg | 1 tsp = 5 mL | 1 cc = 1 mL |
| 1 L = 1000 mL | 1 tbsp = 15 mL = 3 tsp | 1 lb = 16 oz |
| 1 kg = 1000 g | 1 oz = 30 mL | 1 inch = 2.54 cm |
| 1 cup = 8 oz = 240 mL | 1 pt = 16 oz = 500 mL |
The sheet gives 1 pt = 16 oz = 500 mL, and also 1 oz = 30 mL — which makes 16 oz equal 480 mL, not 500. (A true pint is 473 mL.) Use the figure for the unit the question asks in, and do not convert between pints and ounces. When a table contradicts itself, notice it rather than assuming you slipped.
To a smaller unit, multiply — the number gets bigger. To a larger unit, divide — the number gets smaller. Check the direction before you check the arithmetic: a weight in kilograms larger than the pounds you started with is wrong regardless of the digits.
Worked example · two metric rungs at once
0.04 g = ? mcg
- Grams to milligrams: 0.04 × 1000 = 40 mg.
- Milligrams to micrograms: 40 × 1000 = 40,000 mcg.
FINAL ANSWER: 40,000 mcg
One rung at a time. Six decimal places in a single jump is where this goes wrong.
Worked example · household, and an answer that is not in millilitres
A jug holds 200 mL. Record it in ounces.
- 200 ÷ 30 = 6.666…
- The answer is in ounces, not millilitres, so it keeps two decimal places.
FINAL ANSWER: 6.67 oz
Writing 6.7 oz applies the millilitre rule to a unit it does not govern.
Worked example · a dose asked for in teaspoons
Order: cefdinir 300 mg p.o. q12h. Available: 100 mg/5 mL. The parent measures in teaspoons.
- Volume: (300 ÷ 100) × 5 mL = 15 mL.
- Convert: 15 ÷ 5 = 3 tsp.
FINAL ANSWER: 3 tsp (15 mL) per dose
Answer in the unit asked for — and send an oral syringe home, because a kitchen teaspoon holds 2.5 to 7 mL.
Worked example · a weight that does not divide cleanly
A patient weighs 168 lb.
- 168 ÷ 2.2 = 76.3636…
- Round kilograms to the nearest tenth, now, before any dose math.
FINAL ANSWER: 76.4 kg
Section 03
The three methods
One problem, three ways to set it up. Pick one and stay with it — switching mid-exam is how steps get dropped.
Formula method
Desired is the ordered dose, Have is the strength on the label, Quantity is the form that strength comes in — 1 tablet, 1 capsule, 5 mL, 1 mL, 0.5 mL. Quantity is the term people forget, and it is why a “per 5 mL” label gives an answer five times too small when it is ignored.
Ratio and proportion
Worked example · ratio and proportion
Order: amoxicillin 400 mg p.o. Available: 250 mg per 5 mL.
- Set the proportion, units aligned: 250 mg / 5 mL = 400 mg / x mL.
- Cross-multiply: 250x = 400 × 5 = 2000.
- Solve: x = 2000 ÷ 250 = 8 mL.
FINAL ANSWER: 8 mL
Estimate first: 400 mg is a little more than 250, so expect a little more than 5 mL. The arithmetic is identical to the formula method; the layout just makes the units visible.
Dimensional analysis
No formula: chain conversion factors so every unit cancels except the one you want. It is the only method that scales cleanly to three- and four-step problems.
Writing 1 kg / 2.2 lb inside the chain leaves nowhere to round the weight — but the program requires kilograms rounded to the nearest tenth before the dose is calculated. Convert and round the weight as its own first step, then start the chain from the rounded kilograms. For 137 lb the two routes diverge: rounding first gives 62.3 × 5 ÷ 10 = 31.2 mL, and an unbroken chain gives 31.1 mL. Only the first matches the key.
Worked example · dimensional analysis on a multi-step order
Order: amoxicillin 40 mg/kg/day p.o. divided q8h. Child: 66 lb. Available: 200 mg/5 mL.
- Weight first, rounded: 66 ÷ 2.2 = 30 kg.
- Chain the rest so every unit cancels but mL:
5 mL 40 mg 1 day ------- × ------- × ------- × 30 kg 200 mg 1 kg 3 doses
- Numerator: 5 × 40 × 30 = 6000. Denominator: 200 × 3 = 600.
- 6000 ÷ 600 = 10 mL.
FINAL ANSWER: 10 mL per dose
The 1 day / 3 doses factor is how “divided q8h” enters the chain — q8h is three doses a day, not eight.
If the order is roughly double the label strength, expect roughly double the quantity. An estimate will not catch a small slip, but it catches every tenfold one — and tenfold is the error that harms patients.
Section 04
Intake and output
On the exam: NUR 110 2 · NUR 130 1 · 220/230/240 1
Arithmetic more than dosing, and marks are lost on what counts rather than on the sums.
- Intake is oral fluids, ice chips, tube feeds and flushes, IV fluids, IV medications, and irrigant left behind.
- Output is urine, emesis, liquid stool, drains and measurable wound drainage.
- Ice chips count as about half their volume. A 240 mL cup records as 120 mL.
- Everything is charted in millilitres, even when the tray is labelled in ounces.
Worked example · a replacement order
Order: for every 125 mL of urine output, replace with 40 mL of water via PEG tube. Output for the interval is 500 mL.
- How many whole units of output: 500 ÷ 125 = 4.
- Replacement: 4 × 40 = 160 mL.
FINAL ANSWER: 160 mL
A replacement order is a ratio, not a fixed volume.
Intake 1850 mL against output 2200 mL is negative 350 mL, not “350 mL”. The sign is the clinical information.
Section 05
Oral medications
On the exam: NUR 110 6 · NUR 130 3 · 220/230/240 3
Six questions on the NUR 110 exam — the largest single blueprint row. Solids and liquids follow different rules.
Solids
- Only a scored tablet may be halved; an unscored one cannot be split accurately, and the answer there is to ask pharmacy for the right strength.
- Capsules are never split or opened to make a dose.
- More than three tablets for one dose is worth re-reading the order and the label. Three is a perfectly ordinary answer — 0.75 mg from 0.25 mg tablets is three — so treat the count as a prompt to check, not as evidence of an error.
Liquids
- Read the vehicle: per 1 mL and per 5 mL differ fivefold.
- Measure in an oral syringe or a calibrated cup, never a household spoon.
- Read a medicine cup at eye level, at the bottom of the meniscus, on a flat surface.
- Suspensions are shaken thoroughly — unshaken, the first doses are weak and the last are toxic.
Worked example · a buried conversion
Order: ampicillin 0.5 g p.o. q6h. Available: 250 mg per 5 mL.
- Convert the order into the label's unit: 0.5 g = 500 mg.
- (500 ÷ 250) × 5 mL = 10 mL.
FINAL ANSWER: 10 mL per dose
Treating 0.5 as the desired dose gives 0.01 mL — an answer too small to draw, which is itself the warning.
An order of 600 mg p.o. b.i.d. with 300 mg capsules is 2 capsules per dose and 4 in a day. Read which the question wants; the frequency in the stem is there to tempt you into the other one.
Section 06
SubQ, IM and IV push
On the exam: NUR 110 5 · NUR 130 3 · 220/230/240 3
The same formula as oral liquids. What changes is the volume a site tolerates and the precision the syringe allows.
| Route / site | Usual maximum volume | Syringe |
|---|---|---|
| Subcutaneous | 1 mL | 1 mL tuberculin, hundredths |
| Insulin, subcutaneous | by units, not mL | U-100 insulin syringe |
| IM, adult deltoid | 1 mL | 3 mL, hundredths |
| IM, adult ventrogluteal | 3 mL | 3 mL, hundredths |
| IM, older adult or thin patient | 2 mL | 3 mL, hundredths |
| IM, child | 1 mL | 1–3 mL |
| IM, infant (vastus lateralis) | 0.5 mL | 1 mL tuberculin |
A calculated volume above what the site takes is not bad arithmetic — it is a signal to split the dose between two sites, choose a different site, or question the route. 2.5 mL is unremarkable ventrogluteal and impossible subcutaneously, so the same number can be right or wrong depending on the route in the order.
Insulin is ordered in units and drawn in a syringe marked in units. The arithmetic to turn 8 units of U-100 into 0.08 mL is easy, and doing it is still wrong: every avoidable conversion on a high-alert drug is a chance at a tenfold error. If the insulin syringe is missing, fetch one.
Worked example · a label whose quantity is not 1 mL
Order: heparin 5000 units S.C. q8h. Available: 5000 units per 0.5 mL.
- Desired over have: 5000 ÷ 5000 = 1.
- Times the quantity: 1 × 0.5 mL = 0.5 mL.
FINAL ANSWER: 0.5 mL per dose
Answering 1 mL here doubles the dose. The quantity term is never optional.
For IV push the volume is only half the answer — the rate matters as much. Check the monograph for minutes per millilitre and push against a watch, not by feel.
Sources differ on the ceilings above: some texts allow 2 mL in an adult deltoid and 2 mL subcutaneously. The figures in the table are the conservative ones taught in fundamentals, and CCAC's own documents state no limits at all — so treat a volume near the ceiling as a prompt to check the site and the route, not as a number to defend.
Section 07
Reconstitution
On the exam: NUR 110 2 · NUR 130 2 · 220/230/240 1
A powder has no concentration until you add diluent. Every calculation uses the yield printed on the vial, never the diluent volume.
- Read the yield the label promises for the diluent you are adding — often several options on one vial.
- Add exactly that diluent, of exactly that type. Sterile water and bacteriostatic saline are not interchangeable.
- Calculate the dose against the yield.
- Label the vial with the concentration, the date and time mixed, and your initials.
Worked example
A 1 g vial reads “add 3.5 mL to yield 250 mg/mL.” Order: Ancef 500 mg I.M.
- Concentration after mixing: 250 mg/mL.
- (500 ÷ 250) × 1 mL = 2 mL.
FINAL ANSWER: 2 mL
The 3.5 mL is a mixing instruction and never enters the dose calculation.
Worked example · a vial offering two yields
A 1 g vial reads “add 1.8 mL for 500 mg/mL, or 4.8 mL for 250 mg/mL.” Order: 500 mg I.M.
- At 500 mg/mL: 500 ÷ 500 = 1 mL — suits a deltoid.
- At 250 mg/mL: 500 ÷ 250 = 2 mL — suits a ventrogluteal site and is easier to measure accurately.
- Choose one deliberately, write that concentration on the vial, and calculate from it alone.
FINAL ANSWER: either 1 mL at 500 mg/mL or 2 mL at 250 mg/mL — but only the yield you wrote down
A reconstituted multi-dose vial without a concentration and a mix time has to be thrown away, however much drug is left in it. The next nurse cannot calculate from it safely, and the carton's expiry describes the powder, not your solution.
From NUR 220 the question usually continues: mix the vial, withdraw the dose, add it to a minibag, set a rate. The drug volume adds to the bag volume — 2 mL into a 50 mL bag is 52 mL infused.
The expiry you write on the vial
A reconstituted vial keeps for a stated time — often 24, 48 or 72 hours refrigerated, sometimes far less at room temperature. The person who mixes it owns that label, and the exam can ask you to work out when it lapses. Give the answer in military time, and name the day if it crosses midnight.
Worked example
You reconstitute at 0930. The label says the solution is stable for 48 hours refrigerated.
- 48 hours is two whole days, so the clock time does not move.
- Write the date two days on, at 0930, plus your initials and the concentration.
FINAL ANSWER: expires 0930, two days after mixing
For an odd interval, add the hours to the clock and subtract 2400 if you pass midnight: 1600 plus 18 hours is 3400, which is 1000 the next day.
If the label gives no yield for the diluent volume you have, the answer is check the package insert — not to improvise a concentration. And note that the diluent volume and the final volume are not the same number: the powder itself occupies space, so adding 65 mL can produce 100 mL of solution. That is why the yield is printed separately, and why you never calculate from the diluent.
Section 08
Insulin
On the exam: NUR 110 2 · NUR 130 2 · 220/230/240 3
High-alert, and the one drug where the right syringe removes the arithmetic instead of adding to it.
- A U-100 insulin syringe is graduated in units. Draw to the mark; there is nothing to convert.
- U-100 means 100 units/mL. U-500 is five times that, and a U-100 syringe's markings do not apply to it.
- Insulin doses on a standard U-100 syringe are whole units.
- Never write “U” for units in an order.
Sliding scale
Read the band the glucose falls into and give exactly what that band says. The printed ends belong to their own band, so a reading one point either side of a boundary is a different dose.
Worked example · a sliding-scale lookup
Order: Humulin R regular insulin S.C. a.c. per sliding scale.
| Blood glucose (mg/dL) | Coverage |
|---|---|
| under 150 | no coverage |
| 150–200 | 2 units |
| 201–250 | 4 units |
| 251–300 | 6 units |
| 301–350 | 8 units |
| over 350 | hold and call the provider |
- The pre-breakfast reading is 236 mg/dL.
- 236 sits in the 201–250 band.
FINAL ANSWER: 4 units of regular insulin S.C. before breakfast
On this scale 250 is the top of the 4-unit row and 251 starts the 6-unit row. A reading of 250 gets 4 units; 251 gets 6.
Above the top band the order is to hold and call the provider; below the lowest it is no coverage, which is an instruction and not a gap. Extrapolating the pattern upward is the dangerous answer, and so is giving “the highest dose on the scale”. A glucose under 70 is hypoglycaemia: treat it with 15 g of fast-acting carbohydrate, recheck in 15 minutes, and do not give insulin.
Mixing two insulins
- Inject air into the cloudy (NPH) vial, then into the clear (regular) vial.
- Draw the clear insulin first, then the cloudy: clear before cloudy.
- The second mark on the barrel is the cumulative total: 8 units regular plus 32 units NPH means the plunger stops at 8, then at 40.
The air and the drug go in opposite orders, which is exactly what gets examined — and once the two are mixed an overdraw cannot be corrected. Long-acting insulins such as glargine are never mixed with anything.
Worked example · insulin drip NUR 220+
Bag: 100 units regular insulin in 250 mL. Order: 6 units/hr.
- Concentration: 100 ÷ 250 = 0.4 units/mL.
- Rate: 6 ÷ 0.4 = 15 mL/hr.
FINAL ANSWER: 15 mL/hr
Assuming 1 unit/mL because the last bag was mixed that way would run this at 6 mL/hr, under half the ordered dose.
Section 09
IV flow rates
On the exam: NUR 110 — · NUR 130 5 · 220/230/240 5
Five questions on every exam from NUR 130 on, and not examined at NUR 110. Four relationships cover all of it. NUR 130+
The drop factor is printed on the tubing packaging: macrodrip sets are 10, 15 or 20 gtt/mL, a microdrip set is always 60 gtt/mL.
With a 60 gtt/mL set the drop rate and the hourly rate are the same number, because the 60 in the formula cancels the 60 minutes. If those two disagree on a microdrip question, you have slipped.
Worked example · rate and drops together
Order: 1000 mL I.V. over 12 hours, 15 gtt/mL set.
- Rate: 1000 ÷ 12 = 83.33 → 83 mL/hr.
- Drops, from the unrounded rate: (83.33 × 15) ÷ 60 = 20.83 → 21 gtt/min.
FINAL ANSWER: 83 mL/hr and 21 gtt/min
Worked example · finishing time
A 1000 mL bag starts at 0800 at 100 mL/hr.
- Duration: 1000 ÷ 100 = 10 hr.
- 0800 + 10 hr = 1800. If the total passes 2400, subtract 2400 and name the next day.
FINAL ANSWER: 1800
A secondary (piggyback) bag hangs higher than the primary so gravity favours it; its rate is calculated the same way, usually over 30 or 60 minutes.
The drop-factor constant — the short way CCAC hands out
Divide 60 by the set's drop factor once, and you have a constant you can divide into any hourly rate:
| Drop factor | 10 | 15 | 20 | 60 |
|---|---|---|---|---|
| Constant (60 / factor) | 6 | 4 | 3 | 1 |
At 125 mL/hr on a 15 gtt/mL set: 125 / 4 = 31 gtt/min — the same answer as the long form, in one step. The microdrip constant is 1, which is another way of saying the drop rate and the hourly rate are the same number.
The 15-second count
Nobody counts drops for a full minute. Divide the drop rate by four and count for fifteen seconds: 60 gtt/min / 4 = 15 drops in fifteen seconds. Reverse it to read a running line — 12 drops counted in fifteen seconds is 12 x 4 = 48 gtt/min.
When an infusion falls behind
A bag that is late is not recalculated from the original order. Work out what is left, over the time that is left.
Worked example
1000 mL was to run over 6 hours from 0700. At 1000, only 300 mL has gone in.
- Volume remaining: 1000 - 300 = 700 mL.
- Time remaining: 0700 + 6 hr = 1300, and it is now 1000, so 3 hours.
- New rate: 700 / 3 = 233.3 → 233 mL/hr.
FINAL ANSWER: 233 mL/hr
Check the new rate against the patient before you set it. A large catch-up rate is a reason to call, not a number to program — fluid status, cardiac and renal history all outrank finishing on schedule.
Section 10
Complex two-step problems
On the exam: NUR 110 — · NUR 130 5 · 220/230/240 —
Five questions on the NUR 130 exam. It has no row of its own at NUR 220 and above, where two-step work is folded into the oral and parenteral rows instead — so the thinking here matters at every level after 110, even when the blueprint does not name it. NUR 130
What makes a problem “two step” is only that something is buried: a unit to convert, a weight in pounds, a daily dose to divide, or a ceiling that overrides the arithmetic.
- Pounds to kilograms, rounded to the tenth.
- Kilograms to a dose, using the ordered mg/kg.
- Daily dose divided by the number of doses, if the order is per day.
- Dose to volume, using the label.
- Compare against any stated maximum, and give the smaller.
Worked example · daily dose, divided
Order: 30 mg/kg/day p.o. divided q12h. Child: 44 lb. Available: 250 mg/5 mL.
- Weight: 44 ÷ 2.2 = 20 kg.
- Daily dose: 30 × 20 = 600 mg.
- q12h is two doses: 600 ÷ 2 = 300 mg per dose.
- Volume: (300 ÷ 250) × 5 = 6 mL.
FINAL ANSWER: 6 mL per dose
q12h is two doses a day, not twelve. The number in the abbreviation is the interval.
A range in mg/kg/day is compared against the daily total, not against one dose. Checking a single dose against a daily range is what makes an unsafe order look safe. If the order falls outside the range, holding it and querying it is the answer — giving it and documenting a concern is not.
Section 11
Heparin
On the exam: NUR 110 — · NUR 130 — · 220/230/240 4
Four questions on every exam from NUR 220 on — more than any topic except IV rates. Heparin is weight-based, protocol-driven, and independently double-checked every time. NUR 220+
Weight first, then units, then millilitres — and read the bag in front of you. The same 25,000 units comes in 250 mL (100 units/mL) and in 500 mL (50 units/mL), so one order gives two different pump rates.
Worked example · bolus and drip
Order: bolus 80 units/kg, then 18 units/kg/hr. Patient: 75 kg. Vial: 10,000 units/mL. Bag: 25,000 units in 500 mL.
- Bolus: 80 × 75 = 6000 units = 6000 ÷ 10,000 = 0.6 mL.
- Drip dose: 18 × 75 = 1350 units/hr.
- Bag concentration: 25,000 ÷ 500 = 50 units/mL.
- Rate: 1350 ÷ 50 = 27 mL/hr.
FINAL ANSWER: 0.6 mL bolus, then 27 mL/hr
Protocols cap boluses. If 60 units/kg gives 6000 units and the protocol caps at 4000, the dose is 4000 units. The arithmetic will hand you an overdose without complaint.
Convert the ordered change into units per hour first, add it to the current units per hour, then turn the total back into millilitres. Adjusting the millilitres directly gives a dose nobody ordered. And an independent double check means the second nurse calculates it themselves — being shown your number and agreeing is not a check.
Section 12
Titrated drips
On the exam: NUR 110 — · NUR 130 — · 220/230/240 1
One question on the exam from NUR 220 on, and the whole of critical care underneath it. These are the drugs where a decimal error changes a blood pressure in seconds. NUR 220+
Convert the bag to micrograms first: 50 mg in 250 mL is 50,000 mcg in 250 mL, or 200 mcg/mL. Doses are ordered per minute and pumps run per hour — the ×60 is the step that gets dropped.
Worked example · weight-based titration, and why rounding once matters
Dopamine 400 mg in 250 mL. Order: 5 mcg/kg/min. Patient: 137 lb.
- Weight, rounded to the tenth first: 137 ÷ 2.2 = 62.3 kg.
- Concentration: 400,000 ÷ 250 = 1600 mcg/mL.
- Dose: 5 × 62.3 = 311.5 mcg/min, or × 60 = 18,690 mcg/hr.
- Rate: 18,690 ÷ 1600 = 11.68 → 12 mL/hr.
FINAL ANSWER: 12 mL/hr
CCAC's IV sheet says to round mL/hr to whole numbers, titration included, so 11.68 is written as 12. The rounding that decides the answer happened earlier: carrying 62.3 kg rather than 62 moves the unrounded rate from 11.63 to 11.68. Both give 12 here, but on other numbers that gap straddles a boundary. Round the weight once, at the start, and nothing downstream depends on luck.
At every handover: rate × concentration ÷ 60 ÷ weight gives the dose the patient is actually receiving. It is how a mis-programmed pump is found. Know the rate that matches the ordered ceiling before you start titrating, so you recognise the top of the order without recalculating under pressure.
An order already written per hour — nicardipine 5 mg/hr, say — needs no ×60. Applying a remembered formula instead of reading the units is its own error.
Titration orders usually give a range: 2 to 10 mcg/min, titrate to effect. Set the lowest rate first and work up only as the response requires. The top of the range is a ceiling, not a target, and it may not be exceeded without a new order. An item that asks for the rate at each end of a range is asking for two calculations from the same concentration.
Section 13
Equipment: cups, syringes and cartridges
Several exam questions do not stop at the number: they ask you to show it on the device. Marking the wrong line is a wrong answer even when the arithmetic was right.
The medicine cup
Cups are printed in millilitres and household units together — typically 5 mL (1 tsp), 10 mL (2 tsp), 15 mL (1 TBS), 20 mL, 30 mL (2 TBS). Calculate the dose in millilitres, then find the ring that matches. Read at eye level, at the bottom of the meniscus, with the cup on a flat surface.
The 1 mL tuberculin syringe versus the 3 mL syringe
The 1 mL tuberculin syringe is graduated in hundredths, and CCAC's rule is to calculate to the thousandths and round there. A 3 mL syringe is marked in tenths; 5 and 10 mL syringes are marked in fifths — one line every 0.2 mL — even though the arithmetic is still carried to the hundredth. A dose of 0.45 mL needs the 1 mL syringe: on a 3 mL barrel you would be guessing between two lines, and rounding it to 0.5 mL is an 11% overdose. Choosing the device is part of the calculation.
Prefilled cartridges (TUBEX and similar)
A cartridge usually holds more than the ordered dose. Calculate the volume you need, expel the excess to that graduation before injecting, and have a witness for a controlled substance. The question asks for the graduation you keep, not the amount you discard.
The insulin syringe
Marked in units, so there is nothing to convert. When two insulins are mixed, the first mark is the clear (regular) dose and the second is the cumulative total: 8 units regular plus 32 units NPH stops at 8, then at 40. There is no way to remove an overdraw once they are mixed.
“Circle the amount on the cup.” “Circle the amount on the TUBEX.” “Select syringe A or B and mark it with two arrows.” Work the dose first, then answer the question the stem asked — which line, which syringe, which mark.
Section 14
Formula sheet
Everything above, on one screen.
| Answer in… | Round to |
|---|---|
| mL, greater than 1 | Nearest tenth |
| mL, less than 1 | Nearest hundredth |
| Ounces, teaspoons, other non-mL volumes | As the key writes it — 6.67 oz (6 2/3); 6.7 oz also satisfies the stated rules |
| gtt/min | Whole drop |
| mL/hr | Whole mL, titration included |
| Tablets | Whole, or half if scored |
| Capsules | Whole only |
| Insulin units | Whole unit |
| Kilograms | Nearest tenth, before the dose math |
| Clock time | Four-digit military time |
| Syringe | Calculated to | Use it for |
|---|---|---|
| 1 mL tuberculin | Thousandths, rounded to hundredths | Doses under 1 mL |
| 3, 5, 10 mL | Hundredths | Doses over 1 mL |
| U-100 insulin | Whole units | Insulin only |
Section 15
Beyond the blueprint
None of this is on a CCAC dosage exam. All of it turns up on NCLEX, in ATI pharmacology, and on the floor. It is hidden unless you pick the last button, so it never competes with revision. Not examined
Body surface area
Some drugs — chemotherapy above all — are dosed per square metre rather than per kilogram, because surface area tracks metabolic rate better than weight does.
Round BSA to the nearest hundredth, then carry the unrounded figure into the dose where you can. A 70 kg adult of 170 cm is about 1.82 m2; a 20 kg child of 100 cm is about 0.75 m2.
Percent and ratio strengths
- Percent means grams per 100 mL. A 5% solution is 5 g per 100 mL, so a 500 mL bag holds 25 g. The shortcut worth carrying: percent x 10 = mg/mL, so 2% lidocaine is 20 mg/mL.
- A ratio is grams per millilitres. 1:1000 means 1 g in 1000 mL, which is 1 mg/mL; 1:10,000 is 0.1 mg/mL. Adrenaline comes in both, and the two are used by different routes — confusing them is a classic code-situation error.
- Sodium chloride: 0.9% is 9 g per litre, 0.45% is half that, 3% is hypertonic and 23.4% is a concentrate that must be diluted before use.
Pediatric maintenance fluids
The daily method: 100 mL/kg for the first 10 kg, 50 mL/kg for the next 10, 20 mL/kg for every kilogram after that, then divide by 24 for the hourly rate. The hourly shortcut gives the same answer: 4 mL/kg/hr, 2, then 1.
Worked example
A child weighs 26 kg.
- First 10 kg: 10 x 100 = 1000 mL.
- Next 10 kg: 10 x 50 = 500 mL.
- Remaining 6 kg: 6 x 20 = 120 mL.
- Daily total 1620 mL, so 1620 / 24 = 67.5 → 68 mL/hr.
FINAL ANSWER: 1620 mL/day, 68 mL/hr
The hourly rule checks it: (4 x 10) + (2 x 10) + (1 x 6) = 66 mL/hr, near enough to confirm no step was dropped.
Heparin flushes
Flush syringes come in 10 units/mL and 100 units/mL, and they are not interchangeable with the vials used for treatment. A port flush is a small dose — typically around 10 units — and picking up a therapeutic vial instead of a flush is one of the best documented fatal medication errors there is. Read the strength on the flush itself, every time.
Insulin action times
| Type | Onset | Peak | Duration |
|---|---|---|---|
| Rapid-acting (lispro, aspart, glulisine) | 10–30 min | 30 min–3 hr | 3–5 hr |
| Short-acting (regular) | 30 min–1 hr | 2–5 hr | 5–8 hr |
| Intermediate (NPH) | 1–2 hr | 4–12 hr | 14–24 hr |
| Long-acting (glargine, detemir) | 1–4 hr | no pronounced peak | up to 24 hr |
The peak is when hypoglycaemia is most likely, which is what makes these times worth knowing: rapid-acting insulin is given with food in front of the patient, and a missed tray after a morning dose of NPH is a problem in the early afternoon. Note that some sources file glargine as intermediate-acting — it is long-acting, and its defining feature is the absence of a pronounced peak.
Two devices the exam does not use
- A 0.5 mL tuberculin syringe exists and is the right choice for very small volumes; the program's material stops at 1 mL.
- 20 mL and larger syringes are graduated in whole or half millilitres, so they cannot deliver a tenth-place answer at all.
- Some tablets are quarter-scored. The rule stands: only split on a score line.
Built from the CCAC Drug Dosage Calculation Guideline & Blueprint and the program's dosage references. Worked examples are written for this guide.