Written to NHA's CPT test plan
- Safety and Compliance 26%
- Patient Preparation 20%
- Routine Blood Collections 28%
- Special Collections 12%
- Processing 14%
Free · 2026 · 28% of the NHA CPT Phlebotomy Routine Blood Collections practice questions
Routine Blood Collections is 28% of the NHA CPT. Answer 10 questions (6 on Routine Blood Collections) and see your score by domain, with every answer explained. Free, no sign-up.
A new phlebotomist draws a lavender-top (K2EDTA) tube for a CBC and then a gold-top SST for a comprehensive metabolic panel from the same venipuncture. The chemistry results show a very high potassium and a low calcium, and the patient has no symptoms. Which error most likely explains these results?
Tap an answer, or press A to D
Needles and tubes, additives, the order of draw, tourniquet and venipuncture technique, complications, capillary punctures and labeling. The biggest domain.
What the NHA CPT exam tests in Routine Blood Collections
- Collection equipment: evacuated tube system, multisample needles (gauge and length), tube holders, syringes and transfer devices, winged (butterfly) sets, needle safety devices; choosing equipment by vein size, patient condition and requisition; checking sterility, expiration dates, cracks and defects
- Evacuated tubes: stopper colors, additives and what they do (sodium citrate, clot activator, gel separator, heparin, EDTA, sodium fluoride/potassium oxalate), common tests for each tube, fill level and blood-to-additive ratio, number of inversions
- Venipuncture order of draw (CLSI) and why it matters (additive carryover), discard tubes with winged sets
- Venipuncture technique: tourniquet application and the 1-minute limit, palpation, antiseptic application and drying, anchoring the vein, bevel up and insertion angle, filling and mixing tubes, releasing the tourniquet, needle removal and safety-device activation, applying pressure
- Adapting collections for special needs: burns, scars, dementia, bleeding disorders and anticoagulants, obesity, fragile or rolling veins, children and older adults; minimum-volume tubes required by analyzers
- Problems and complications: no blood flow (needle position, lost vacuum, collapsed vein), hematoma, petechiae, nerve pain, accidental arterial puncture, syncope, diaphoresis, nausea, seizures, prolonged bleeding; when to stop the draw
- Dermal (capillary) puncture: when to use it and when not to, finger and heel sites, puncture depth, warming, wiping the first drop, avoiding squeezing, capillary order of draw, microcollection containers
- Post-procedure care and labeling: confirming bleeding has stopped, bandaging (allergies, skin type, age), post-procedure precautions and hydration, labeling every specimen at the patient's side
- Core knowledge applied to collection: cardiovascular system and blood flow, structure of veins and arteries, hemostasis and coagulation, blood components (whole blood, serum, plasma, cells), ABO and Rh blood groups, phlebotomy medical terminology
High-yield routine blood collections facts
- Gauge: a higher number means a smaller bore. 21 G = standard adult; 22 G = small adult veins and children; 23 G = usual winged set (hand, pediatric, geriatric, fragile veins). Smaller than 23 G risks hemolysis and slow flow. 16-17 G = blood donation.
- Needle length: multisample needles are usually 1-1.5 in; winged sets 1/2-3/4 in.
- The multisample needle's rubber sleeve stops leakage between tubes. The tube holder is single-use and discarded with the needle attached.
- Winged set uses: small or hand veins, children, older adults, awkward positions. The tubing holds air (dead space).
- Syringe: for fragile or collapsing veins; pull the plunger slowly. Transfer with a SAFETY TRANSFER DEVICE in the order of draw and let the tube vacuum fill it. Never push the plunger (hemolysis, stopper pop) or push a needle through a stopper.
- Before use: check the sterility seal is intact, the tube expiration date (expired = lost vacuum, degraded additive), and for cracks and needle burrs. Discard dropped or cracked tubes.
| Stopper | Additive and action | Common tests | BD inversions |
|---|---|---|---|
| Culture bottles / yellow SPS | Broth / SPS (anticoagulant; inhibits complement and some antibiotics) | Blood cultures | Per maker (SPS 8-10) |
| Light blue | 3.2% sodium citrate; binds Ca; 9:1 fill | PT/INR, aPTT, fibrinogen, D-dimer | 3-4 |
| Red glass | None; clots naturally | Serum, some blood bank | 0 |
| Red plastic | Silica clot activator | Serum chemistry, serology, drug levels | 5 |
| Gold / tiger SST | Clot activator + gel | Serum chemistry, serology | 5 |
| Orange RST | Thrombin; clots in about 5 min | STAT serum chemistry | 5-6 |
| Green | Sodium or lithium heparin; inhibits thrombin | Plasma chemistry, STAT, ammonia | 8-10 |
| Light green / green-gray PST | Lithium heparin + gel | Plasma chemistry | 8-10 |
The full Phlebotomy High-Yield Cram Sheet comes with full prep.
Common routine blood collections traps
- Tourniquet: 3-4 in above the site, 1 min max, released BEFORE the needle comes out.
- Wet alcohol hemolyzes the specimen; let it air-dry.
- Bevel up, 30° or less; anchor below the site with the thumb, never above and below.
- Light blue must be filled to the line (9:1); winged set + light blue drawn first = discard tube.
- Order of draw tests additive categories (serum vs heparin vs EDTA), not red vs gold inside a category.
- EDTA carryover raises K and lowers Ca; hemolysis and fist pumping also raise K.
- Gray is LAST in the venous order; capillary order puts EDTA FIRST and serum LAST.
- Invert gently, never shake; glass red = 0 inversions; light blue = 3-4 (BD).
Free Phlebotomy routine blood collections practice questions
Question 1
While a tube is filling, the phlebotomist notices a rapidly enlarging, raised swelling forming around the needle site. What is the most appropriate response?
- AAdvance the needle deeper so the bevel is fully inside the vein
- BKeep collecting because blood is still flowing into the tube
- CRelease the tourniquet, remove the needle, and apply firm pressure
- DHave the patient bend the elbow tightly with the needle in place
Show answer and explanation
Answer: C. A swelling around the site means blood is leaking into the tissue, so the procedure is stopped and pressure is applied to limit the hematoma.
Why not A: Probing deeper may push the needle through the back wall of the vein and worsen the bleeding into tissue. A forming hematoma means the draw should stop.
Why not B: Continued flow does not mean the site is safe. Blood leaking into tissue will keep enlarging the hematoma, and the specimen may be compromised.
Why not D: Bending the elbow does not stop the leak, and it is dangerous with a needle in the arm. Bending the arm after a draw also encourages hematoma formation.
Remember: A hematoma forming during a draw means stop: release the tourniquet, remove the needle, and apply direct pressure.
Question 2
A phlebotomist is drawing an inpatient whose arm is propped up on two pillows. During the draw, the tube sits higher than the puncture site, with the stopper end pointing down and blood resting against the stopper. What is the best action?
- ATighten the tourniquet so the extra venous pressure blocks any backflow
- BReposition the arm to angle downward so the tube stays below the site and fills from the bottom up
- CKeep the arm raised, because elevation increases venous pressure and speeds filling
- DLeave the position as it is, since reflux matters only for blood culture bottles
Show answer and explanation
Answer: B. Keeping the tube lower than the site prevents reflux of tube contents, including additives, into the patient's vein.
Why not A: Tightening the band does not correct the tube position and adds the risk of hemoconcentration.
Why not C: Raising the arm reduces venous filling, and a tube held above the site allows its contents to flow back toward the vein.
Why not D: Reflux matters with additive tubes as well, because additive can be pushed back into the patient's circulation.
Remember: Keep the arm angled down and the tube below the puncture site so it fills from the bottom up and nothing flows back into the vein.
Question 3
The laboratory's test directory states that an ordered hepatitis antibody panel must be performed on serum. Which tube should the phlebotomist collect?
- ALavender-top tube (K2EDTA)
- BGold-top tube (clot activator with gel)
- CLight-green-top tube (lithium heparin with gel)
- DLight-blue-top tube (sodium citrate)
Show answer and explanation
Answer: B. The clot activator lets the blood clot, and once it is spun the gel separates serum from the cells.
Why not A: EDTA prevents clotting, so this tube gives whole blood or plasma rather than serum.
Why not C: Heparin is an anticoagulant, so this tube yields plasma, not serum.
Why not D: Sodium citrate is an anticoagulant used for coagulation plasma, so it cannot provide serum.
Remember: Serum comes only from clotted blood (plain or clot activator tubes); any tube with an anticoagulant yields plasma or whole blood.
Question 4
A phlebotomist uses a syringe to draw a patient with small veins that collapse easily. After removing the needle and activating its safety device, how should she fill the evacuated tubes?
- APush the syringe needle through each stopper and press the plunger to fill the tubes in order
- BAttach a safety transfer device and let each tube's vacuum pull the blood in, in the order of draw
- CRemove each stopper and gently pour the blood into the tubes, then recap them in order
- DAttach a safety transfer device and press the plunger firmly to speed filling, in the order of draw
Show answer and explanation
Answer: B. A safety transfer device prevents needlesticks. Letting the vacuum fill each tube avoids hemolysis and keeps the blood-to-additive ratio correct.
Why not A: Pushing a needle through stoppers by hand risks a needlestick. Forcing blood through the needle can hemolyze the specimen.
Why not C: Removing stoppers exposes the worker to splashes and destroys the tube vacuum, so the fill volumes and ratios are uncontrolled.
Why not D: The transfer device is right, but pushing the plunger hemolyzes the blood and can overfill tubes or pop stoppers.
Remember: Transfer syringe blood with a safety transfer device and let the tube vacuum, not the plunger, fill the tubes in order of draw.
Question 5
A patient with small hand veins needs only a PT/INR. You plan to use a winged (butterfly) collection set with a tube holder, and the light blue-top (3.2% sodium citrate) tube is the only tube ordered. What should you do?
- AFill the light blue tube first and invert it extra times to make up for any underfill
- BDraw a gold-top SST first as the discard tube, then fill the light blue tube
- CDraw a discard tube (non-additive or another citrate tube) first, then fill the light blue tube
- DHold the light blue tube above the site so the air in the tubing escapes as it fills
Show answer and explanation
Answer: C. The discard tube clears air from the tubing so the light blue tube fills to the line with the correct 9:1 ratio.
Why not A: Extra inversions can't correct an underfilled tube. Air in the tubing short-fills the citrate tube, so the 9:1 blood-to-citrate ratio is still wrong.
Why not B: An SST contains clot activator. Using it before a citrate tube risks carryover that can falsely shorten clotting times.
Why not D: Tubes must be held below the site to prevent reflux. Holding the tube up does not remove the air from the tubing.
Remember: When a light blue tube is the first tube drawn with a winged set, draw a non-additive or citrate discard tube first so the citrate tube fills completely.
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