Phlebotomy Practice Questions and Answers (NHA CPT)

Answer: B. Blood culture, coagulation tube, SST, heparin, EDTA, glycolytic inhibitor

Blood culture, coagulation, SST, heparin, EDTA, then glycolytic inhibitor is the CLSI order of draw. Sterile culture bottles go first so no nonsterile stopper contaminates them, and the citrate tube precedes every tube whose clot activator, heparin or EDTA could carry over and change clotting times. The SST-first sequence places the serum and EDTA tubes ahead of the culture bottle. The coagulation-first sequence draws the culture third and EDTA before the SST. The EDTA-first sequence lets EDTA carry over into the SST, citrate and culture specimens.

Source: CLSI PRE02 — Order of Draw

Answer: C. Lavender

Lavender (purple) stoppers mark EDTA tubes, used for CBCs and hemoglobin A1c. EDTA chelates calcium, which stops clotting while keeping blood cells intact for counting and smear review. Red stoppers hold no additive or a clot activator for serum. Light blue stoppers hold sodium citrate for PT and aPTT. Green stoppers hold lithium or sodium heparin for plasma chemistry.

Source: NHA CPT Test Plan — Section 3B: Tube Additives

Answer: B. Blood culture bottle

The blood culture bottle comes first. Cultures must be drawn before any nonsterile tube so organisms from a stopper or holder cannot enter the bottle and cause a false positive. The red-top serum tube follows the culture and the coagulation tube in the CLSI sequence. The green-top heparin tube comes after the serum tube. The lavender EDTA tube for the CBC goes near the end, after heparin and before gray.

Source: CLSI PRE02 — Order of Draw

Answer: C. Heparin

Green-top tubes contain lithium or sodium heparin, which blocks clotting by boosting antithrombin activity against thrombin. They give plasma for chemistry panels and are often used when a fast turnaround matters. Sodium citrate belongs to light blue coagulation tubes. Sodium fluoride, a glycolysis inhibitor, belongs to gray tubes. EDTA belongs to lavender tubes for hematology.

Source: NHA CPT Test Plan — Section 3B: Tube Additives

Answer: B. Red-top serum tube

The correct answer is red-top serum tubes, which contain no anticoagulant or a clot activator only. Blood clots naturally and serum is harvested after centrifugation. Lavender EDTA, green heparin, and blue citrate tubes all contain anticoagulants that prevent clotting, so they yield plasma or whole blood rather than serum. Selecting the wrong tube produces a specimen the analyzer may reject for chemistry panels.

Source: NHA CPT Test Plan — Section 3B: Tube Additives

Answer: A. Lavender-top tubes contain EDTA for hematology tests

CBC testing uses the lavender (purple) top, which contains EDTA to keep cells intact and unclotted for counts and smears. Light blue tops hold sodium citrate and are used for coagulation studies such as PT and aPTT. Green tops contain heparin and serve plasma chemistry. Gray tops contain sodium fluoride with potassium oxalate to preserve glucose; none of these three is the standard hematology tube.

Source: NHA CPT Test Plan — Section 3B: Tube Additives

Answer: D. Sodium citrate at a 9:1 blood-to-additive ratio

Light blue tops contain sodium citrate, and the tube must be filled so blood and additive are in a 9:1 ratio for PT and aPTT. Citrate binds calcium reversibly, and the lab adds calcium back during testing. Fluoride with oxalate is the gray-top glucose preservative. Lithium heparin is the green-top additive and would interfere with clotting tests. Potassium EDTA is the lavender-top additive, and no additive is acceptable in any fill volume.

Source: NHA CPT Test Plan — Section 3B: Tube Additives

Answer: B. Invert SST tubes gently five times

Most SSTs are inverted gently five times to mix the clot activator with the blood. Violent shaking hemolyzes the sample. An SST left unmixed may clot slowly or unevenly. Thirty forceful inversions are unnecessary and can damage the cells. Five gentle turns are enough.

Source: NHA CPT Test Plan — Section 5A: Specimen Handling

Answer: D. Fluoride blocks glycolysis for accuracy

Sodium fluoride inhibits enolase, an enzyme in glycolysis, so cells stop using up glucose and the result stays close to the level at collection. EDTA prevents clotting for hematology but does not stop glycolysis. Heparin only blocks clotting; the cells in the tube go on using glucose. Glucose in serum left on the clot drops by roughly 5 to 7 percent per hour until it is separated.

Source: NHA CPT Test Plan — Section 3B: Tube Additives

Answer: D. To distend the veins by restricting venous blood flow

The correct answer is to distend the veins by restricting venous blood flow. A tourniquet is applied 3-4 inches above the venipuncture site to impede venous return while allowing arterial flow to continue. This causes veins to fill and become more visible and palpable for needle insertion. Numbing the skin is not a function of the tourniquet. Increasing arterial flow is the opposite of what occurs. Cleaning the skin is performed with an antiseptic swab, not a tourniquet. The tourniquet should not remain in place longer than one minute.

Source: NHA CPT Test Plan — Section 3C: Venipuncture Procedure

Answer: C. The median cubital vein in the antecubital fossa

The correct answer is the median cubital vein of the antecubital fossa. It is large, well anchored, and lies away from major nerves and arteries, making it the safest first choice. Hand veins are smaller and roll more easily. The basilic vein sits near the brachial artery and median nerve, raising injury risk. Leg and foot veins carry higher thrombosis risk and are avoided unless no upper-extremity site exists.

Source: CLSI PRE02 — Site Selection

Answer: B. 15 to 30 degrees with the bevel facing up

The correct answer is 15 to 30 degrees with the bevel facing up. This shallow angle enters the vein cleanly without passing through its far wall. A steep 45-degree angle increases through-and-through puncture and hematoma risk. Bevel-down orientation tears tissue and blocks blood flow. Inserting parallel to the skin may skim above the vein, while a deep perpendicular stick risks nerve or arterial injury.

Source: CLSI PRE02 — Needle Insertion Angle

Answer: A. 21-gauge needle for routine adult antecubital venipuncture

The correct answer is a 21-gauge needle for routine adult antecubital draws. It balances reliable flow with acceptable comfort, minimizing hemolysis risk. A 16-gauge needle is excessively large and painful for routine collection. A 25-gauge needle creates high shear forces that rupture red cells and slow filling, inviting clotting. Butterfly sets are reserved for fragile, hand, or difficult veins rather than routine antecubital access.

Source: CLSI PRE02 — Needle Selection

Answer: A. It lies near the brachial artery and the median nerve

The basilic vein is the last antecubital choice because it lies close to the brachial artery and the median nerve, and it rolls easily. It is often large and easy to fill, so small size is not the problem. Valves exist in many veins and do not make the basilic vein a poor choice. Blood from the basilic vein contains no more tissue fluid than blood from other arm veins.

Source: CLSI PRE02 — Site Selection

Answer: A. Notify the ordering physician and do not draw the fasting specimen

Notify the ordering physician and hold the fasting draw. A fasting lipid panel assumes no food for 8-12 hours, and a recent meal raises triglycerides in particular. Drawing anyway and writing non-fasting on the tube still produces a result the order did not ask for. The lab has no way to correct a lipid result for a meal after the fact. Sending the patient home to return tomorrow may be the outcome, but that decision belongs to the physician, who must be told why the draw was not done.

Source: NHA CPT Test Plan — Section 2D: Patient Preparation and Assessment

Answer: A. Have the patient state name and birth date, then match wristband and requisition

Ask the patient to state their full name and date of birth, then compare both with the wristband and the requisition. Active identification with two identifiers catches mix-ups before blood is drawn. A door sign can be out of date and does not prove who is in the bed. A coworker's recognition is not an identifier and can be wrong. Room and bed numbers change with transfers and are never accepted as identifiers.

Source: The Joint Commission — NPSG.01.01.01: Two Identifiers

Answer: A. Explain the draw, confirm consent, and answer questions calmly

The correct answer is explaining the procedure, confirming consent, and answering questions calmly. Informed consent respects autonomy and reduces anxiety, which lowers vasovagal risk. Proceeding while a patient actively refuses violates consent and may constitute battery. Restraint by staff is never appropriate for routine collection. Skipping explanation to save time increases fear, movement, and the chance of injury or failed venipuncture.

Source: NHA CPT Test Plan — Section 2C: Communication and Consent

Answer: C. Confirm the required fast was completed before starting the test

Confirm the fast before starting; when the patient has eaten, the test is not started and the provider is told so it can be rescheduled. A glucose tolerance test compares timed samples to a fasting baseline, and breakfast makes the baseline high. Noting the meal and running the test still gives results that cannot be interpreted. Water is allowed during the fast but does not undo a meal. Drawing right away assumes the physician can correct for food, which no correction can do.

Source: NHA CPT Test Plan — Section 4D: Glucose Tolerance Testing

Answer: B. Pale sweaty skin with nausea and lightheadedness

Vasovagal syncope usually announces itself with pallor, sweating, nausea, and lightheadedness, giving time to stop the draw and protect the patient from falling. Hives, itching, and wheezing after antiseptic contact point to an allergic reaction. Rapid swelling at the site means a hematoma, which calls for removing the needle and applying pressure. Electric pain shooting into the fingers suggests nerve contact and is also a reason to stop.

Source: NHA CPT Test Plan — Section 3G: Adverse Reactions

Answer: C. Small-gauge butterfly with gentle draw pressure

Thin, fragile veins in older adults tolerate a small-gauge butterfly with gentle pull far better than standard equipment. A large-bore needle tears the vessel wall and raises the chance of a hematoma. Leaving the tourniquet on for minutes bruises fragile skin and concentrates the sample. Pulling hard on a syringe collapses the vein and can hemolyze the blood.

Source: NHA CPT Test Plan — Section 3E: Special Collection Methods

Answer: A. Two identifiers such as name and date of birth

Two identifiers, such as full name and date of birth, are confirmed with the patient before any tube is drawn, and the patient states them rather than agreeing to them. A name alone is not enough because patients can share names. Room and bed numbers are locations, not identifiers, and change when a patient moves. Recognizing a familiar face is not a verification step and can lead to a wrong-patient draw.

Source: The Joint Commission — NPSG.01.01.01: Two Identifiers

Answer: A. Supine with the legs elevated

A patient who faints is lowered to a lying position with the legs raised, which brings blood back to the brain and prevents a fall. Putting the head between the knees while seated is a weaker measure, and the patient can still slide out of the chair. Sitting fully upright keeps blood pooled in the legs. Standing with arms raised is the worst choice because the patient may collapse again.

Source: NHA CPT Test Plan — Section 3G: Adverse Reactions

Answer: A. The needle has contacted or entered a nerve

Contact with a nerve is the most likely cause. Tingling, numbness or shooting pain that starts once the needle is in the antecubital area points to the median nerve or a nearby branch, and the needle should be removed at once. A large needle gauge makes insertion more painful but does not produce nerve symptoms in the hand. Brisk blood flow into the tube causes no sensation at all. A tourniquet tight enough to block arterial flow would also stop blood return into the tube, and its discomfort would center on the band.

Source: NHA CPT Test Plan — Section 3F: Difficult Collections

Answer: B. Draw from the right arm with a routine venipuncture

A restricted-extremity band means that arm is not used for venipuncture, blood pressures or IVs, so the draw is made from the other arm. Drawing from the left arm ignores the restriction. The hand is part of the same restricted limb. Refusing delays care when the unrestricted arm is available; the provider is contacted only if neither arm can be used.

Source: NHA CPT Test Plan — Section 2G: Consent and Compliance

Answer: D. 70% isopropyl alcohol followed by chlorhexidine gluconate

Chlorhexidine gluconate with alcohol is the preferred skin prep for blood cultures, because it kills skin flora quickly and keeps working after it dries, lowering contamination rates. Povidone-iodine is an older alternative that needs a longer drying time and is used mainly when chlorhexidine cannot be. A single wipe with 70% alcohol is the routine venipuncture prep and is not enough for a culture. Hydrogen peroxide is not a skin antiseptic for venipuncture.

Source: NHA CPT Test Plan — Section 4A: Blood Cultures

Answer: B. Puncture the medial or lateral plantar heel under 2 mm deep

The correct answer is the medial or lateral plantar heel surface with a depth under two millimeters. These fleshy borders avoid the calcaneus bone while providing rich capillary flow. The posterior curvature sits directly over bone and risks osteomyelitis. Fingers are avoided in infants because of tiny blood volume and injury risk. Earlobes are obsolete capillary sites and yield unreliable samples for modern testing.

Source: CLSI H4-A6 — Capillary Puncture Standard: Section 5

Answer: B. Draw trough specimens just before the next dose

A trough is the lowest drug level of the dosing cycle, so it is drawn just before the next dose is given. Drawing hours after a dose measures something closer to a peak or a mid-level value. A random time cannot be compared with the therapeutic range. Peak levels answer a different question and do not show whether the drug is clearing between doses.

Source: NHA CPT Test Plan — Section 4C: Drug Testing

Answer: D. The middle or ring finger of the non-dominant hand

For adult fingersticks, use the middle or ring finger of the non-dominant hand, puncturing the fleshy pad slightly off center. The index finger is often callused and more sensitive, and it is used constantly. The thumb has a pulse and thicker skin. The earlobe is not a recommended adult capillary site.

Source: CLSI H4-A6 — Capillary Puncture Standard: Section 5

Answer: B. The EDTA container, then the serum one

For skin punctures CLSI places the EDTA container ahead of other additive and serum containers, because platelets start clumping at the puncture site and hematology counts need the earliest blood. Filling the serum container first leaves the EDTA sample prone to clumps and falsely low platelet counts. The sequence is not optional, since clotting at the site worsens with every second. A single drop cannot properly fill two containers at once.

Source: CLSI GP42 (formerly H4) — Collection of Capillary Blood Specimens

Answer: A. Fibrin strands or micro-clots that can interfere with automated analyzer probes

Spinning an SST before the blood fully clots leaves fibrinogen in the serum, which forms fibrin strands and micro-clots that can block analyzer probes. The gel barrier separates serum from cells but cannot hold back fibrin that forms after the spin. Early centrifugation does not lyse all the red cells, and bright red serum points to hemolysis from another cause. Incomplete clotting has no reason to lower potassium; delays and hemolysis tend to raise it instead.

Source: NHA CPT Test Plan — Section 5B: Centrifugation and Aliquoting

Answer: D. Pink or red discoloration of serum or plasma

The correct answer is visible red-tinged serum or plasma indicating ruptured red cells. Hemolysis releases intracellular potassium, LDH, and hemoglobin that distort many chemistry results, so the laboratory rejects affected specimens. Slightly warm tubes are normal after handling. Small clots in serum tubes are expected before centrifugation. Printed labels confirm good practice rather than a defect.

Source: NHA CPT Test Plan — Section 5D: Specimen Rejection

Answer: A. Bilirubin and other light-sensitive analytes degrading

The correct answer is light-sensitive analytes such as bilirubin degrading in bright light. Photodegradation falsely lowers results, so amber wrapping or prompt delivery preserves accuracy. Red cells do not multiply in daylight. EDTA potency is unaffected by brief light exposure. Clotting accelerates slightly with warmth rather than light, so darkness is specifically about photolabile chemistry rather than general specimen stability.

Source: NHA CPT Test Plan — Section 5C: Specimen Storage

Answer: C. Forcing blood rapidly through a small-gauge needle or shaking tubes vigorously

The correct answer is forcing blood rapidly through a small-gauge needle or shaking tubes vigorously. High shear forces rupture red cell membranes and release intracellular contents, falsely elevating potassium and other analytes. Correct gauge selection, gentle inversions, dried antiseptic, and prompt tourniquet release all reduce hemolysis rather than causing it.

Source: NHA CPT Test Plan — Section 5D: Specimen Rejection

Answer: A. Transmission-based precautions

The correct answer is transmission-based precautions. These are used in addition to standard precautions when a patient is known or suspected to be infected with organisms that are spread via airborne, droplet, or contact routes. Full barrier PPE including gown, gloves, mask, and eye protection may be required depending on the mode of transmission. Standard precautions apply to all patients but do not typically require all four items. Droplet and contact precautions are subsets of transmission-based precautions, not equivalent to the full set.

Source: CDC/HICPAC — Guideline for Isolation Precautions

Answer: A. The patient's treating physician

The correct answer is the patient's treating physician. HIPAA's Privacy Rule permits covered entities to use and disclose protected health information for treatment, payment, and healthcare operations without separate patient authorization. The treating physician falls under the treatment exception. Sharing results with coworkers not involved in care violates minimum necessary standards. The patient's employer and friends have no treatment relationship and require explicit written authorization from the patient to receive any health information.

Source: HIPAA Privacy Rule — 45 CFR 164.506

Answer: C. Within 10 working days of initial assignment

OSHA's bloodborne pathogens standard requires the hepatitis B vaccine series to be offered at no cost within 10 working days of initial assignment to a job with occupational exposure. 24 hours of hire is not the rule, and the clock starts at assignment, not hire. Waiting for an exposure incident defeats the purpose of vaccinating beforehand. An annual screening is not a substitute for the initial offer.

Source: 29 CFR 1910.1030(f)(2)(i)

Answer: D. Testing the phlebotomist's baseline hepatitis A antibody titer

Baseline hepatitis A antibody testing is not part of a bloodborne-pathogen workup, because hepatitis A spreads by the fecal-oral route, not through needlesticks. The OSHA standard and CDC guidance cover HIV, hepatitis B and hepatitis C. Testing the source patient's blood, with consent where state law requires it, tells the clinician what the worker was exposed to. Evaluating and counseling the employee guides prophylaxis and follow-up testing. Documenting the route and circumstances of the exposure is a required part of the evaluation.

Source: OSHA Bloodborne Pathogens Standard — 29 CFR 1910.1030(f)(3)

Answer: B. At least 15 seconds

CDC's guideline for hand hygiene in healthcare settings says to rub hands with soap and water for at least 15 seconds, covering all surfaces, then rinse and dry. 5 seconds is too short to remove soil and microbes. 2 minutes or longer is closer to a surgical scrub, which is not required for routine care. The 20-second figure is CDC's advice for the general public.

Source: CDC — Guideline for Hand Hygiene in Health-Care Settings

Answer: A. Fit-tested N95 respirator with eye protection

The correct answer is an N95 respirator plus eye protection for airborne pathogens such as tuberculosis. Airborne nuclei remain suspended and require fit-tested filtration plus mucous membrane coverage. A surgical mask alone does not filter airborne particles. Gloves alone leave the respiratory tract exposed. No precautions for a confirmed tuberculosis patient endangers staff and violates isolation policy.

Source: CDC/HICPAC — Guideline for Isolation Precautions: Airborne Precautions

Answer: C. Alcohol sanitizer when hands are not visibly soiled

An alcohol-based hand rub is the routine choice whenever hands are not visibly soiled, including before and after each patient and after removing gloves. Gloves do not replace hand hygiene because they can have tiny defects and hands get contaminated during removal. Alcohol rubs kill most bacteria and many viruses quickly, so banning them has no basis. Visible blood is the situation where soap and water are required, not sanitizer.

Source: CDC — Guideline for Hand Hygiene in Health-Care Settings: Section 4