16 Special Collections Practice Questions & Answers
Every Special Collections practice question from the Phlebotomy Technician Practice Test, with the correct answer and a short explanation.
Start practice test →1. Two tubes on the tray have yellow stoppers. How do the yellow SPS tube and the yellow ACD tube differ in use?
- A.SPS is used for coagulation, while ACD is used for glucose tolerance testing
- B.SPS is used for blood cultures, while ACD is used for HLA and paternity testing✓ Answer
- C.SPS is used for blood banking, while ACD is used for routine chemistry panels
- D.SPS is used for trace metals, while ACD is used for therapeutic drug levels
Stopper colour alone does not identify a tube: sodium polyanethol sulfonate is the microbiology anticoagulant that also inhibits complement and phagocytes, while acid citrate dextrose preserves cell viability for HLA typing, paternity and DNA studies. Only the SPS tube belongs in the blood culture position at the head of the order of draw.
Source: CLSI GP41 (PRE02) tube additive tableReport a problem with this question
2. A royal blue trace element tube is included in a multi-tube draw. Where does it belong in the CLSI order of draw?
- A.It is placed by its additive, so an EDTA version draws with the EDTA tubes✓ Answer
- B.It is placed last of all, so the special stopper cannot shed trace metals
- C.It is placed first of all, so no metal from other stoppers can contaminate it
- D.It is placed after the citrate tube, so serum trace levels stay accurate
Royal blue is a stopper made of low-trace-metal material, not a single additive, and the same colour is sold with no additive, with a clot activator, or with EDTA. Order of draw is governed by what is inside the tube, so the clot-activator version draws in the serum position and the EDTA version draws in the EDTA position.
Source: CLSI GP41 (PRE02) placement of trace-element tubesReport a problem with this question
3. Blood cultures are collected with a winged set directly into the bottles. Which bottle is inoculated first and why?
- A.The anaerobic bottle, so the tubing air is expelled before the aerobic fills
- B.The anaerobic bottle, so the strict anaerobes get the largest share of blood
- C.The aerobic bottle, so the vacuum is checked before the anaerobic is filled
- D.The aerobic bottle, so the air in the tubing does not enter the anaerobic one✓ Answer
The tubing of a winged set holds a column of air that enters the first bottle inoculated. Filling the aerobic bottle first sends that air where oxygen does no harm; the order flips when a syringe is used, because there is no tubing air and the anaerobic bottle is filled first.
Source: CLSI GP41 (PRE02) blood culture inoculation; NHA CPT Test PlanReport a problem with this question
4. Skin and bottle preparation for a blood culture on an adult uses which antiseptics?
- A.Chlorhexidine on the skin and 70% alcohol on the bottle tops, both air-dried✓ Answer
- B.Benzalkonium chloride on the skin and 70% alcohol on the bottle tops as well
- C.70% alcohol on the skin and chlorhexidine on the bottle tops, both left to dry
- D.Povidone-iodine on the skin and povidone-iodine on the bottle tops as well
Chlorhexidine gluconate gives the sustained skin antisepsis needed to keep skin flora out of the bottle in patients over two months, and the bottle septum is wiped with 70% alcohol rather than iodine, which can degrade the septum. Both surfaces must air-dry, since a wet antiseptic is not yet working and can be carried into the specimen.
Source: CLSI GP41 (PRE02) blood culture skin and bottle antisepsisReport a problem with this question
5. A legal blood alcohol specimen is ordered. Which antiseptic and tube combination is correct?
- A.A non-alcohol antiseptic with a gray sodium fluoride tube kept capped✓ Answer
- B.A 70% isopropyl alcohol prep with a red plain serum tube kept capped
- C.A 70% isopropyl alcohol prep with a gray sodium fluoride tube kept capped
- D.A non-alcohol antiseptic with a green lithium heparin tube kept capped
An alcohol prep can contaminate the sample and gives the defense an argument that the reading is not the patient's own, so a non-alcohol antiseptic such as benzalkonium chloride or povidone-iodine is used. The gray tube is required because sodium fluoride stops microbial and cellular metabolism that would otherwise change the alcohol concentration, and the tube is not uncapped.
Source: NHA CPT Test Plan, blood alcohol collection; CLSI GP41 (PRE02)Report a problem with this question
6. A blood culture set is being drawn with a winged collection set into paired bottles. Which practice is correct?
- A.Palpate the vein once more after cleaning, then fill whichever bottle is nearer
- B.Scrub with friction, dry the site by fanning it, and fill the anaerobic bottle first
- C.Scrub with friction, let the site dry fully, and inoculate the aerobic bottle first✓ Answer
- D.Underfill both bottles a little so that the broth is not diluted by the blood
The antiseptic kills skin flora only while it is drying, so the prepared site is left to air dry untouched; fanning it or re-palpating it recontaminates the skin and produces false-positive cultures. With winged tubing the air in the line is pushed into the first bottle filled, so the aerobic bottle goes first, and each bottle must receive its full recommended volume because sensitivity depends on volume.
Source: CLSI GP41 blood culture collection; NHA CPT Test PlanReport a problem with this question
7. A blood alcohol specimen is being collected for a legal case. Which practice is correct?
- A.Clean with an alcohol pad, then uncap the tube to check that it filled fully
- B.Clean with a non-alcohol antiseptic and send the tube without any signatures
- C.Clean with an isopropyl alcohol pad and note the collection time on the form
- D.Clean with a non-alcohol antiseptic and complete the chain of custody record✓ Answer
An alcohol-based skin prep can contaminate the specimen and hands the defense an obvious challenge, so an aqueous antiseptic such as benzalkonium chloride or soap and water is used instead. Legal specimens also require an unbroken chain of custody with signatures, dates and times, and the tube is filled and left capped because alcohol evaporates from an opened tube.
Source: NHA CPT Test Plan, legal specimens and chain of custody; CLSI GP41Report a problem with this question
8. What is the recommended blood volume to place in each bottle when collecting an adult blood culture set?
- A.15–20 mL
- B.1–3 mL
- C.8–10 mL✓ Answer
- D.4–6 mL
Adult blood culture bottles should each receive 8–10 mL (about 20 mL per two-bottle set) because bacteremia is often low-level and the chance of detecting organisms rises with the volume of blood cultured. Underfilling is the classic cause of false-negative cultures; 1–3 mL is the pediatric range, not the adult one.
Source: NHA CPT Test Plan (eff. Jan 2026), Domain 4 Task 4A / k77; CLSI M47 — adult blood culture fill volume 8–10 mL per bottle, 1–3 mL pediatricReport a problem with this question
9. A provider orders blood cultures x2 for a patient with suspected sepsis, and IV antibiotics are about to be started. What is the correct collection practice?
- A.Draw both sets from one site after the first antibiotic dose
- B.Draw one set now and the second set after antibiotics begin
- C.Draw both sets from the same vein, thirty minutes apart
- D.Draw both sets from two separate sites before antibiotics begin✓ Answer
Both sets must be collected before antimicrobial therapy starts, because even a single dose can suppress bacterial growth and cause false negatives. Drawing the sets from two separate sites lets the laboratory distinguish true bacteremia (the same organism grows from both sites) from skin-flora contamination at one puncture site.
Source: NHA CPT Test Plan (eff. Jan 2026), Domain 4 Task 4A / k75–k79; CLSI M47 — two sets from separate sites, collected before antimicrobial therapyReport a problem with this question
10. A patient has completed the fasting draw for a 3-hour glucose tolerance test and is given the 100 g glucose drink. When does the timing for the remaining draws start?
- A.At the moment the fasting specimen was collected
- B.When the patient finishes drinking the entire dose✓ Answer
- C.At the moment the drink is handed to the patient
- D.When the patient takes the first sip of the drink
GTT timing starts the moment the patient finishes the entire glucose dose, and every subsequent specimen (1-hour, 2-hour, 3-hour) is timed precisely from that point. Starting the clock at the first sip, the fasting draw, or hand-off shifts every later draw, and mistimed specimens invalidate the glucose curve.
Source: NHA CPT Test Plan (eff. Jan 2026), Domain 4 Task 4H — glucose tolerance test protocol: timing begins when the patient finishes the glucose beverageReport a problem with this question
11. Before collecting several tubes from a premature infant, the phlebotomist consults a weight-based chart provided by the facility. What does this chart specify?
- A.The maximum blood volume that may be safely removed✓ Answer
- B.The minimum fill volume required in each tube type
- C.The smallest needle gauge suitable for infant veins
- D.The maximum puncture depth allowed for a heel stick
Infants have a very small total blood volume (roughly 100 mL/kg), so facilities cap the amount drawn based on body weight and track cumulative losses over 24 hours and 30 days. These limits exist to prevent iatrogenic anemia, which can otherwise require a transfusion; needle gauge, tube fill, and puncture depth are set by other standards, not by this chart.
Source: NHA CPT Test Plan (eff. Jan 2026), Domain 4 Tasks 4B/4E, k80/k83 — weight-based maximum draw volumes to prevent iatrogenic anemia; infant TBV ~100 mL/kgReport a problem with this question
12. Which technique is correct when applying blood to the filter-paper card for newborn metabolic screening?
- A.Fill each printed circle completely with one drop, from one side only✓ Answer
- B.Layer several small drops in a circle until it appears fully soaked
- C.Apply blood to both sides of the card so each circle saturates evenly
- D.Press the card gently against the heel so blood soaks each circle
A single large, free-flowing drop applied to one side of the card soaks through evenly and gives a uniform blood concentration in the spot. Layering multiple drops or applying blood to both sides deposits an uneven amount of analyte and invalidates the specimen, and touching the card directly to the heel contaminates it with tissue fluid.
Source: NHA CPT Test Plan (eff. Jan 2026), Domain 4 Task 4C / k81; CLSI NBS01 — dried blood spot collection: one free-flowing drop per circle, applied to one side onlyReport a problem with this question
13. A trough level is ordered for a patient receiving scheduled doses of vancomycin. When should the phlebotomist draw the specimen?
- A.Thirty minutes after the infusion has finished
- B.Immediately before the next dose is administered✓ Answer
- C.At the halfway point between two scheduled doses
- D.Immediately after the current infusion has finished
A trough is the lowest drug concentration in the dosing cycle, which occurs just before the next dose is given, so the specimen is drawn immediately before that dose. Drawing after or shortly after an infusion captures a peak-range level instead, misrepresenting the true trough and potentially leading the provider to under-dose the patient.
Source: NHA CPT Test Plan (eff. Jan 2026), Domain 4 — therapeutic drug monitoring: trough drawn immediately before the next scheduled doseReport a problem with this question
14. During a urine drug screen collected under chain-of-custody protocol, which step is the collector required to perform?
- A.Read the specimen's temperature within about 4 minutes of collection✓ Answer
- B.Store the donor's belongings inside the restroom during collection
- C.Refrigerate the specimen for 15 minutes before sealing the container
- D.Seal the specimen out of the donor's sight to prevent interference
The temperature must be read within about 4 minutes and fall in the 90–100 °F range, because fresh urine cools quickly — a reading outside that window suggests a substituted or adulterated specimen. The container is sealed with tamper-evident tape in the donor's presence (never out of sight), and the donor's belongings stay outside the restroom.
Source: NHA CPT Test Plan (eff. Jan 2026), Domain 4 Task 4J / k86; DOT 49 CFR Part 40 — urine temperature checked within 4 minutes, acceptable range 90–100 °FReport a problem with this question
15. How long must a donor wait after giving whole blood before donating whole blood again?
- A.4 weeks
- B.16 weeks
- C.8 weeks✓ Answer
- D.2 weeks
The standard deferral between whole-blood donations is 8 weeks (56 days), because removing a ~450–500 mL unit takes a significant amount of red cells and iron, and the body needs that interval to rebuild red cell mass and iron stores. Shorter intervals apply only to certain apheresis procedures, not whole blood.
Source: NHA CPT Test Plan (eff. Jan 2026), Domain 4 Task 4D / k82; FDA 21 CFR 640.3 / AABB standards — 8-week (56-day) interval between whole-blood donationsReport a problem with this question
16. A patient is starting a 24-hour urine collection at home. Which instruction is correct?
- A.Collect only the first-morning specimen on two consecutive days
- B.Discard the first void, then collect all urine for the next 24 hours✓ Answer
- C.Keep the container at room temperature throughout the collection
- D.Collect the first void but discard the final void at the 24-hour mark
The first void is discarded because that urine was formed before the timing window began; the clock starts at that moment, and every void afterward — including the final void exactly at the 24-hour mark — goes into the container. Reversing this (keeping the first, discarding the last) skews the timed total, and the container should generally be kept refrigerated or on ice, not at room temperature.
Source: NHA CPT Test Plan (eff. Jan 2026), Domain 4 Task 4F / k84 (patient instruction crossover, Task 2P) — 24-hour urine: discard first void, collect all urine including the final void; keep refrigeratedReport a problem with this question
Concept-focused practice questions based on CLSI GP41 (venous blood collection), the CLSI order of draw, and the OSHA Bloodborne Pathogens Standard (29 CFR 1910.1030). Not affiliated with the NHA, ASCP, or CLSI, and not medical advice. Facility protocols and current CLSI standards take precedence — always follow your employer's procedures. About the CPT exam →