Point of Care Testing and Laboratory Procedures — practice questions

6% of the exam ≈9 real questions 9 free questions here

9 scored items. CLIA-waived testing, quality control, urinalysis and the common rapid tests. The recurring theme is that a result is only valid if the process around it was valid.

Where people lose points

• Quality control is run and documented before patient testing, not after a result looks strange.
• A clean-catch midstream specimen requires specific patient instruction — many questions test whether you can give that instruction correctly.
• Urinalysis has three distinct parts: physical, chemical and microscopic. Know which findings belong to which.
• Expired reagents and strips invalidate a result even when the number looks plausible. Check dates as part of the procedure.
• CLIA-waived does not mean unregulated — waived tests still require manufacturer instructions to be followed exactly.

Questions and answers, explained

All 7 questions above, with the correct answer and why it is correct. Everything here is on point of care testing and laboratory procedures.

1. Which test may a medical assistant perform in a physician office laboratory that holds a CLIA Certificate of Waiver?

   • AManual white blood cell differential on a stained smear
   • BMicroscopic examination of urine sediment
   • CGram stain of a wound specimen
   • DNonautomated dipstick urinalysisCorrect

   Why: Nonautomated dipstick or tablet reagent urinalysis is explicitly listed as waived under CLIA at 42 CFR 493.15(c), along with urine pregnancy tests by visual color comparison, fecal occult blood, spun microhematocrit, and blood glucose by FDA-cleared home-use meters. Manual differentials and Gram stains are higher-complexity tests, and urine microscopy is a provider-performed microscopy procedure; none may be performed under a Certificate of Waiver.

   Reference Domain 3D; k114 CLIA-waived testing regulations; CMS 42 CFR 493.15(c) waived test list

2. Which practice is required of a physician office laboratory performing waived testing?

   • AFollow the manufacturer's package insert exactly, including timing, storage, and quality control frequency.Correct
   • BModify the procedure to fit clinic workflow as long as the results look reasonable.
   • CUse reagent strips from one manufacturer with an analyzer from another to reduce cost.
   • DPerform calibration only when a result appears clinically unexpected.

   Why: Waived status depends entirely on performing the test exactly as the manufacturer instructs; any modification, such as changed timing, mixed-brand reagents, or altered storage, makes the test high complexity and takes the laboratory outside its Certificate of Waiver. Calibration and calibration verification are performed on the schedule in the insert, not only when a result looks surprising, because a drifting instrument produces plausible-looking wrong answers.

   Reference Domain 3D; k114 CLIA-waived testing regulations; k142 equipment calibration; CMS Certificate of Waiver requirements

3. A patient is starting a 24-hour urine collection at 7:00 a.m. Which instruction should the medical assistant give?

   • ACollect the 7:00 a.m. void and stop collecting at 7:00 a.m. the next day.
   • BCollect only the voids during waking hours and keep it at room temperature.
   • CDiscard the first void, collect all the rest through 7:00 a.m., keep it cold.Correct
   • DCollect every void for 24 hours and pour off any excess so the container does not spill.

   Why: The first void is discarded because it contains urine the kidneys produced before the timed interval began, and the final void at the 24-hour mark is included so the interval is complete; the container is kept refrigerated or on ice throughout to prevent analyte degradation and bacterial growth. A single missed or discarded void (A, B, D) makes the quantitative result falsely low and the collection must be repeated.

   Reference Domain 3D; k113 specimen collection techniques; k121 storage requirements; 24-hour timed urine collection standard

4. Which technique should be used to collect a throat swab for a rapid strep test?

   • ASwab the tongue and the inside of both cheeks.
   • BSwab the tonsils and posterior pharynx, avoiding the tongue, cheeks, and lips.Correct
   • CSwab the anterior nares and then the back of the throat with the same swab.
   • DHave the patient rinse with mouthwash, then swab the uvula.

   Why: Group A streptococci are recovered from the tonsillar surfaces and posterior pharynx, so the swab is rubbed firmly over both tonsils and the back of the throat. Touching the tongue, cheeks, or lips (A, C) dilutes the sample with saliva and normal flora and lowers sensitivity, which produces a false negative and can leave a treatable strep infection undiagnosed. Rinsing with mouthwash first (D) can also reduce recovery of the organism.

   Reference Domain 3D; k113 specimen collection techniques; IDSA group A streptococcal pharyngitis guideline (tonsils and posterior pharynx)

5. A rapid mononucleosis test detects which substance in the patient's specimen?

   • AEpstein-Barr virus DNA
   • BAtypical lymphocytes
   • CHeterophile antibodiesCorrect
   • DCold agglutinins

   Why: The rapid, CLIA-waived mono test is a heterophile antibody test performed on whole blood, serum, or plasma. Because heterophile antibodies may not be detectable during the first week of illness, an early negative result does not rule out infectious mononucleosis and the provider may repeat it later. Atypical lymphocytes are seen on a stained blood smear, not on the rapid test, and Epstein-Barr DNA testing is a send-out molecular assay.

   Reference Domain 3D; k111 point-of-care testing; CLIA-waived heterophile antibody mononucleosis test

6. Which hemoglobin and hematocrit results fall within the typical adult reference range for a nonpregnant woman?

   • AHemoglobin 13.0 g/dL, hematocrit 39%Correct
   • BHemoglobin 8.2 g/dL, hematocrit 25%
   • CHemoglobin 18.5 g/dL, hematocrit 56%
   • DHemoglobin 10.5 g/dL, hematocrit 31%

   Why: Typical adult reference intervals are roughly 12 to 16 g/dL hemoglobin with a 36% to 46% hematocrit for women, and roughly 14 to 18 g/dL with a 42% to 52% hematocrit for men, so 13.0 g/dL with a 39% hematocrit is within range. Choices B and D are consistent with anemia and choice C with polycythemia; all out-of-range values are documented and reported to the provider. Intervals vary by method, age, and altitude, so always compare against the reference interval published by the testing laboratory.

   Reference Domain 3D; k116 in-range and out-of-range laboratory values; standard adult hemoglobin and hematocrit reference intervals (laboratory specific)

7. A medical assistant is preparing an adult for a pure-tone audiometry screening. Which action is correct?

   • ATell the patient to respond only when a tone is loud and clearly comfortable.
   • BSeat the patient facing the audiometer so the dial shows when a tone plays.
   • CPlace the red earphone on the right ear and have the patient signal each tone.Correct
   • DStart at the loudest setting and hold it there so no frequency is missed.

   Why: Audiometer earphones are color coded, red for the right ear and blue for the left, and reversing them documents the loss in the wrong ear. The screening is done in the quietest room available, and the patient is told to raise a hand or press the response button every time a tone is heard, however faint. An adult screening is a fixed-level pass/fail procedure, not a search for thresholds: tones are presented at 25 dB HL at 1,000, 2,000, and 4,000 Hz, and an absent response at any one of those frequencies in either ear is a fail that triggers referral for a full audiologic evaluation. Telling the patient to answer only when a tone is loud and comfortable (A) hides the faint tones the screen depends on and produces a false fail. Holding the intensity at maximum (D) guarantees a response to everything, so the screen detects nothing. The patient is also positioned so the audiometer dial and the examiner's hands are out of view (B), because visual cues produce false responses. The medical assistant performs and records the screening; the provider or audiologist interprets it.

   Reference Domain 3D; 3D6 perform vision and hearing tests; k118 elements related to vision and hearing tests; ASHA adult pure-tone hearing screening (red = right ear, blue = left ear; 25 dB HL at 1000, 2000, and 4000 Hz; any absent response in either ear = refer)

Topics inside this domain

• Medical assistant scope of practice
• Injection routes, sites and angles
• Vaccine cold chain and storage
• Specimen labeling and patient identification

Drill other domains

• Foundational Knowledge and Basic Science (10%)
• Anatomy and Physiology (5.3%)
• Patient Intake and Vitals (9.3%)
• General Patient Care (18.7%)
• Infection Control and Safety (10%)
• Phlebotomy (8%)

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