Free Medical Laboratory Assistant (MLA) examination Practice Questions

Sample Practice Questions

Try these 10 sample questions from the Medical Laboratory Assistant (MLA) examination practice bank. Each includes the answer and explanation. Continue with the interactive practice above to review the full question set.

1. 1While accessioning a nonwaived chemistry test, an assistant finds a specimen and patient demographics but no order. Which documentation normally authorizes the laboratory to perform the requested patient testing?

   1. A. A written or electronic request from an authorized person
   2. B. A signed consent form authorizing collection of the specimen
   3. C. A clinical progress note documenting the patient's diagnosis
   4. D. An electronic registration recording the patient's requested test

   Answer: A

   Explanation: The regulation states, "The laboratory must have a written or electronic request for patient testing from an authorized person." Consent to collection, a diagnosis note, or patient registration does not replace an authorized testing request.

   Reference: 42 CFR § 493.1241 — Standard: Test request — § 493.1241(a)

2. 2A fresh liquid stool specimen is submitted for observing motile trophozoites. Under CDC guidance, what is the latest recommended examination time measured from passage?

   1. A. 15 minutes
   2. B. 30 minutes
   3. C. 60 minutes
   4. D. 120 minutes

   Answer: B

   Explanation: CDC specifies that liquid specimens "should be examined within 30 minutes of passage". The clock starts at passage, rather than laboratory arrival.

   Reference: DPDx — Stool Specimens: Specimen Processing — Fresh specimen examination, liquid specimens

3. 3An assistant labels a freshly prepared reagent for a nonwaived assay. Which date information must appear when applicable under CLIA?

   1. A. The reagent's receipt date and first-use date
   2. B. The reagent's order date and delivery date
   3. C. The reagent's preparation date and expiration date
   4. D. The reagent's opening date and initial-control date

   Answer: C

   Explanation: CLIA reagent labeling includes "Preparation and expiration dates." Receipt, ordering, opening and initial-control dates do not replace that required pair.

   Reference: 42 CFR Part 493 — Laboratory Requirements — § 493.1252(c)(3)

4. 4An assistant finds a textbook description of an assay that differs from the laboratory's written procedure. What is the textbook's permitted role under CLIA?

   1. A. It replaces the local procedure when its instructions are more detailed
   2. B. It supplements the local procedure without replacing it
   3. C. It replaces the local procedure when the assay principle is unchanged
   4. D. It replaces the local procedure when the manufacturer instructions agree

   Answer: B

   Explanation: CLIA states, "Textbooks may supplement but not replace the laboratory's written procedures for testing or examining specimens." Personnel must follow the laboratory's applicable written procedure.

   Reference: 42 CFR Part 493 — Laboratory Requirements — § 493.1251(a)

5. 5An assistant follows up an oral request for a nonwaived laboratory test. Under CLIA, within how many days of that oral request must the laboratory solicit written or electronic authorization?

   1. A. 10 days
   2. B. 30 days
   3. C. 60 days
   4. D. 90 days

   Answer: B

   Explanation: CLIA permits oral requests if the laboratory "solicits a written or electronic authorization within 30 days of the oral request". Thirty days is the deadline for solicitation; obtaining authorization and documenting efforts remain required by the full provision.

   Reference: 42 CFR § 493.1241 — Standard: Test request — § 493.1241(b)

6. 6A patient has just received barium, and an assistant is checking suitability for a stool parasite examination. Which clearance interval does CDC identify for barium's interfering effects?

   1. A. 1–2 days
   2. B. 3–5 days
   3. C. 7–10 days
   4. D. 14–21 days

   Answer: C

   Explanation: CDC lists "barium or bismuth (7-10 days needed for clearance of effects)". A recent barium exposure must be considered when assessing the specimen.

   Reference: DPDx — Stool Specimens: Specimen Collection — Collection guidance — interfering drugs and compounds

7. 7All storage conditions are appropriate and the printed expiration date has not passed. Which reagent condition independently prohibits its use for nonwaived patient testing under CLIA?

   1. A. Deterioration of the reagent
   2. B. First opening of the reagent container
   3. C. Receipt of a new reagent shipment
   4. D. Introduction of a new reagent lot

   Answer: A

   Explanation: CLIA states that supplies "must not be used when they have exceeded their expiration date, have deteriorated, or are of substandard quality." Deterioration is independently disqualifying; routine opening, receipt or lot introduction is not itself deterioration.

   Reference: 42 CFR Part 493 — Laboratory Requirements — § 493.1252(d)

8. 8An assistant is preparing to implement a revised nonwaived testing procedure. Whose approval, signature, and date are required before the revision is used?

   1. A. The current laboratory director's
   2. B. The clinical consultant's
   3. C. The technical supervisor's
   4. D. The general supervisor's

   Answer: A

   Explanation: CLIA requires, "Procedures and changes in procedures must be approved, signed, and dated by the current laboratory director before use." Other parties do not provide that approval.

   Reference: 42 CFR Part 493 — Laboratory Requirements — § 493.1251(d)

9. 9A hospital uses a patient's medical record as authorization for a nonwaived test. An assistant is checking whether that record can serve as the requisition. When must it be available to the laboratory?

   1. A. After analytical testing, before technical review
   2. B. After technical review, before final report release
   3. C. When the final result is released to the requester
   4. D. When the laboratory performs the requested testing

   Answer: D

   Explanation: The rule states that the medical record "must be available to the laboratory at the time of testing". Availability only during later review or report release is too late.

   Reference: 42 CFR § 493.1241 — Standard: Test request — § 493.1241(d)

10. 10A stool specimen was refrigerated without preservative because preservative was unavailable. For which test category does CDC describe this exception as suitable?

    1. A. Antigen testing
    2. B. Motility testing
    3. C. Permanent staining
    4. D. Larval culture

    Answer: A

    Explanation: CDC describes unpreserved refrigerated specimens as "suitable for antigen testing only." Refrigeration in this exception does not establish suitability for the other methods.

    Reference: DPDx — Stool Specimens: Specimen Collection — Immediate processing and refrigeration exception