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Phlebotomy (CPT) guide · updated 2026-09-29

How many questions are on the NHA CPT phlebotomy exam?

The NHA CPT exam has 120 multiple-choice questions, of which 100 are scored and 20 are unscored pretest items, and you get 2 hours to answer them. The 100 scored items are split across five domains, with Routine Blood Collections the largest at 28 items.

The short version

  • 120 questions in total.
  • 100 scored questions that decide pass or fail.
  • 20 pretest questions that NHA is trying out for future exams. They do not count, and you cannot tell which ones they are.
  • 2 hours of testing time, which works out to about one minute per question.
  • Current version live since January 7, 2026, built on a 2024 job analysis of working phlebotomists.

How the 100 scored questions are split

NHA publishes the exact number of scored items per domain. Because there are exactly 100 scored items, the counts double as percentages.

DomainScored itemsShare
Safety and Compliance2626%
Patient Preparation2020%
Routine Blood Collections2828%
Special Collections1212%
Processing1414%
Total100100%

What the questions look like

Items are multiple choice with one best answer. NHA says items may test recall or critical thinking about a task or a knowledge statement in the test plan, so expect a mix of straight facts (which additive is in a gray-top tube) and short scenarios (a patient reports tingling down the arm after the needle goes in, what do you do first).

A handful of items involve simple numbers: fill ratios, timed draws in a glucose tolerance test, or the most blood you may take from a small child. None of it needs more than basic arithmetic, but the pediatric volume items trip up people who have never set them up on paper.

Pacing the 2 hours

With 120 questions in 120 minutes you have one minute each. Most recall items take 20 to 30 seconds, which banks time for the scenario items. A practical plan is to be past question 60 by the one-hour mark, flag anything you are unsure of, and come back at the end.

Because you cannot tell which 20 items are unscored, treat every question as if it counts. A strange-looking question on a topic you never studied may well be a pretest item, so do not let it shake you.

Practice at the real length

Short quizzes are good for learning a topic, but the real exam is a two-hour sitting. At least once before test day, take a full 120-question timed mock so you know how your focus holds up in the second hour. The mocks on this site use that same length and the same domain weights.

Sample Phlebotomy (CPT) questions with answers

1. Which additive is found in a lavender-top evacuated tube, and what is its primary mechanism of anticoagulation?

  1. Sodium citrate — binds calcium ions to prevent clotting
  2. Lithium heparin — inhibits thrombin and activated Factor X
  3. Ethylenediaminetetraacetic acid (EDTA) — chelates calcium ions to prevent clotting
  4. Sodium fluoride — inhibits glycolytic enzymes to preserve cell morphology
Show answer

C. Ethylenediaminetetraacetic acid (EDTA) — chelates calcium ions to prevent clotting Lavender-top tubes contain EDTA (most commonly dipotassium EDTA, K2EDTA), which chelates ionized calcium essential for coagulation, preventing clotting while preserving cellular morphology for hematology tests such as the CBC. Sodium citrate (light-blue tube) also binds calcium but is reserved for coagulation testing. Lithium heparin (green tube) inhibits thrombin for plasma chemistry panels. Sodium fluoride (gray tube) preserves glucose by inhibiting glycolysis, not by chelating calcium.

2. A phlebotomist is selecting tubes for a fasting glucose test. Which tube additive specifically inhibits glycolysis to preserve glucose concentrations after collection?

  1. Potassium EDTA
  2. Lithium heparin
  3. Sodium citrate
  4. Sodium fluoride
Show answer

D. Sodium fluoride Sodium fluoride inhibits the glycolytic enzyme enolase, halting cellular metabolism of glucose; it is paired with potassium oxalate (an anticoagulant) in gray-top tubes. Without this preservative, glucose in whole blood decreases approximately 10 mg/dL per hour at room temperature as cells continue metabolizing glucose. EDTA (lavender) and lithium heparin (green) are general anticoagulants not designed for glucose preservation; sodium citrate (light-blue) is used exclusively for coagulation testing.

3. A phlebotomist is ordered to collect blood cultures, a prothrombin time (PT/INR), and a CBC. According to the CLSI venipuncture order of draw, which sequence is correct?

  1. Light blue → blood cultures → lavender
  2. Blood cultures → light blue → lavender
  3. Blood cultures → lavender → light blue
  4. Lavender → blood cultures → light blue
Show answer

B. Blood cultures → light blue → lavender CLSI GP41 places sterile blood culture bottles first to prevent additive carryover from contaminating the sterile specimen, light blue sodium citrate second because the critical citrate-to-blood ratio must not be disrupted by carryover, and EDTA (lavender) last among these three. Options A and D do not place blood cultures first; option C reverses the light blue and lavender positions.

Frequently asked questions

Are all 120 questions scored?

No. 100 are scored and 20 are pretest items that do not affect your result. They are mixed in and not marked.

How long is the NHA CPT exam?

You have 2 hours of testing time for the 120 questions.

Did the number of questions change in 2026?

The new CPT exam that went live on January 7, 2026 keeps the 100 scored plus 20 pretest format and the 2 hour time limit. What changed is the test plan behind it, which now comes from a 2024 job analysis.

Try the free Phlebotomy (CPT) practice test

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Sources: NHA CPT Test Plan (2024 job analysis, exam live January 7, 2026) · NHA: New CPT certification exam and study materials. Independent study material. Not affiliated with or endorsed by the National Healthcareer Association.

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NHA and National Healthcareer Association are trademarks of the National Healthcareer Association. ExamWeight is an independent study resource and is not affiliated with, endorsed by, or sponsored by NHA. Questions are original and written against the published Certified Phlebotomy Technician (CPT) test plan.