Phlebotomy Special Collections
Updated October 27, 2026
Special Collections is its own domain on the NHA CPT exam. These are collections with extra steps: special timing, special handling after collection, or extra paperwork. Here’s what to know, followed by free practice questions. Always follow your laboratory’s procedure manual, which sets the exact requirements.
Blood cultures
- Used to look for bacteria or fungi in the blood.
- Skin antisepsis is critical to avoid contaminating the sample with skin bacteria. Follow your facility’s antiseptic, scrub method and drying time.
- Disinfect the tops of the culture bottles.
- Blood cultures come first in the order of draw.
- Usually collected as sets, often from separate sites or at separate times, as ordered.
Timed and fasting collections
| Type | Key point |
|---|---|
| Fasting | The patient must not eat for a set time first; confirm before drawing and note it if they haven’t fasted |
| Timed draws | Collected at a specific time; record the exact collection time |
| Glucose tolerance test | A fasting sample, then a glucose drink, then samples at set intervals |
| Therapeutic drug monitoring | Peak and trough levels, timed in relation to the dose |
Handling after collection
| Handling | Common examples |
|---|---|
| Chilled (in ice slurry) | Ammonia, lactic acid, some blood gases |
| Kept at body temperature | Cold agglutinins, cryofibrinogen |
| Protected from light | Bilirubin, some vitamins such as B12 and folate |
Chain of custody
Specimens for legal purposes, such as drug screens or blood alcohol tests, need a chain of custody: a documented, unbroken record of everyone who handled the specimen, with tamper-evident seals. For blood alcohol tests, don’t clean the site with alcohol; use a non-alcohol antiseptic as your procedure directs.
Free practice questions
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Where do blood cultures fall in the order of draw?Answer: ABlood cultures are collected first so the sample stays sterile and isn't contaminated by other tubes.
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Which specimen is commonly placed in an ice slurry after collection?Answer: CAmmonia is chilled right away because it continues to rise in the tube at room temperature. Cold agglutinins are kept warm, and bilirubin is protected from light.
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Why is a bilirubin specimen protected from light?Answer: BBilirubin breaks down when exposed to light, which can give a falsely low result. Use an amber tube or wrap the tube as your procedure directs.
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What is a chain of custody?Answer: DFor legal specimens such as drug screens, the chain of custody documents every person who handled the specimen, so the result can be defended in court.
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For a blood alcohol test, how should the site be cleaned?Answer: BAn alcohol pad could contaminate the specimen and raise the result, so a non-alcohol antiseptic is used.
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For a trough drug level, when is the blood usually drawn?Answer: CThe trough is the lowest level, usually drawn just before the next dose. The peak is drawn when the level is expected to be highest after a dose. Follow the timing in the order.
Pass your phlebotomy exam on the first try
- All 173 questions on safety, patient preparation, routine and special collections and processing
- An explanation for every answer, with the CLSI standard, OSHA rule or guideline behind it
- Unlimited full 100-question practice exams, with each domain in its real share