Special Collections

12% of the CPT · blueprint NHA CPT Test Plan, based on a job analysis completed in 2024

Short answer

The smallest domain at 12 of the 100 scored items. It covers blood culture collection including skin preparation, equipment, volume and the order of draw for cultures; assisting with pediatric, geriatric and line collections; metabolic screening; blood donation; volume limits for at-risk patients; non-blood specimens; point-of-care testing; tolerance tests; blood alcohol collection; and drug screening.

Why it matters on this exam

Twelve items. This is the domain candidates over-prepare because it sounds hardest, and it is the smallest on the exam. Study it after Routine Blood Collections and Safety and Compliance, which are 54 items between them.

What makes it examinable is that each special collection has one thing that differs from a routine draw, and the exam asks about that difference.

Key concepts

Blood cultures (4A, k75 to k79). Skin preparation is the whole game — contamination produces a false positive and an unnecessary course of antibiotics. Know the techniques and locations for skin prep, the equipment including needle type, hub or adaptor and bottle type, the volume requirements, the bottle preparation procedure, and the order of draw for blood cultures, which the test plan lists separately at k78. In the CLSI order, the blood culture tube or bottle is first.
Assisting with lines (4B, k80). Pediatric, geriatric, non-tunneled and tunneled lines. The task is assisting other healthcare professionals, not performing the line draw yourself.
Metabolic screening (4C, k81). PKU and galactosemia, collected on filter paper, with its own technique.
Blood donation (4D, k82). Donor standards: hemoglobin and hematocrit levels, weight, and complete patient screening.
Volume limits (4E, k83). Calculate or look up volume requirements for patients at higher risk — pediatric, geriatric — to avoid causing illness by the collection itself. Pediatric volume calculation has its own knowledge statement.
Non-blood specimens (4F, k84). Throat cultures, nasal swabs, wound cultures, with their own equipment, methods and processing times.
Point-of-care testing (4G). Hemoglobin and hematocrit, blood glucose screening, urine pregnancy testing, urinalysis.
Tolerance tests (4H). Gestational glucose, lactose, two-hour post-prandial glucose — timing is what these test.
Blood alcohol (4I, k85). The skin preparation is the difference: an alcohol-based antiseptic would compromise the result.
Drug screening (4J, k86). Specimen collection requirements, and in practice chain of custody, which sits in the Processing domain.

Common mistakes

Preparing a blood alcohol site with an alcohol swab. This is the classic item in the domain and the reason skin preparation for blood alcohol has its own knowledge statement.
Treating blood culture volume as flexible. Volume requirements have their own knowledge statement (k77) because under-filling degrades sensitivity.

Worked example

A requisition asks for blood cultures and a CBC from the same draw. Two rules combine. The blood culture bottle comes first in the CLSI order of draw, before the citrate tube and well before the lavender EDTA tube the CBC needs — so cultures first, CBC last of the two. And skin preparation for the culture is more rigorous than for a routine draw, because a contaminated culture produces a false positive that changes the patient's treatment. Getting the order right and the prep wrong still fails the patient.

Original practice questions

Special CollectionsDifficulty 3/5

Why does blood alcohol collection require a specific skin preparation?

AAn alcohol-based antiseptic interferes with the additive in the collection tube
BAn alcohol-based antiseptic is not effective against skin flora at the draw site
CAn alcohol-based antiseptic could contaminate the specimen and raise the result
DAn alcohol-based antiseptic dries too slowly and delays the collection process

Show answer and rationale

Correct: C. Knowledge statement k85 gives skin preparation for blood alcohol its own entry precisely because the routine antiseptic is the contaminant. Blood alcohol work also requires chain of custody.

D — Drying time is a general technique concern and is not why the preparation differs here.
A — The interference is with the analyte being measured, not with the tube additive.
B — Alcohol antiseptics are effective; the problem is what they are made of, not their efficacy.

Special CollectionsDifficulty 3/5

Why is skin preparation especially rigorous for blood culture collection?

ASkin flora entering the bottle produces a false negative and a missed infection
BInadequate preparation reduces the volume of blood the bottle will accept
CInadequate preparation prevents the culture bottle from being drawn first
DSkin flora entering the bottle produces a false positive and unnecessary treatment

Show answer and rationale

Correct: D. A contaminated culture grows organisms from the skin rather than the bloodstream, and the patient is treated for an infection they do not have. That consequence is why techniques and locations for skin prep have their own knowledge statement.

A — Contamination adds organisms rather than masking them, so the error is a false positive.
B — Skin preparation does not affect the vacuum or capacity of the culture bottle.
C — Draw order is set by the CLSI sequence and is unaffected by preparation quality.

Special CollectionsDifficulty 3/5

Why does the test plan require calculating volume requirements for pediatric and geriatric patients?

ATo avoid causing illness in the patient through the volume collected
BTo ensure the laboratory receives the maximum volume each tube allows
CTo determine which closure colour the collection tube should carry
DTo establish how many tube inversions the specimen will require

Show answer and rationale

Correct: A. Task 4E states the purpose directly: calculate or look up volume requirements in patients at higher risk to avoid illness caused by the collection. Pediatric volume calculation has its own knowledge statement at k83.

B — Maximising volume is the opposite of the concern for an at-risk patient.
C — Tube selection follows the test ordered, not the patient's age.
D — Inversion counts come from the tube manufacturer and are unrelated to patient volume.

All 3 Special Collections questions →

Tools for this topic

Order of draw trainer — Draws a random set of tubes and asks you to sequence them, using the order CLSI publishes from GP41. Separate variants for venipuncture, blood cultures and capillary collection, because the NHA test plan lists them as three separate requirements.

4 flashcards for Special Collections

Practice this topic

Blueprint-mapped questions with full rationales for every choice.

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Primary references

NHA Certified Phlebotomy Technician (CPT) — Test Plan for the CPT Exam — National Healthcareer Association (NHA) · primary · retrieved 2026-09-22, verified 2026-09-22
Order of Blood Draw Tubes and Additives — Clinical and Laboratory Standards Institute (CLSI) · primary · retrieved 2026-09-22, verified 2026-09-22

Last reviewed: 2026-09-22Next review by: 2026-11-06Draft — pending editorial reviewHow we verify facts