NCCT Non-Blood Specimen Collection 2 — Questions and Answers
Question 1: Which type of urine specimen is most commonly requested for routine urinalysis?
- 24-hour collection
- Clean-catch midstream
- Random specimen (Correct answer)
- First morning void
Correct answer: Random specimen
A random urine specimen is the most commonly collected type for routine urinalysis because it requires no special preparation and can be collected at any time.
Random urine specimens can be collected at any time without special patient preparation, making them the most practical for routine urinalysis. While first morning voids are more concentrated and preferred for pregnancy testing or microscopic examination, random specimens are sufficient for most screening purposes.
Question 2: When collecting a throat swab for rapid strep testing, where should the swab be applied?
- The tongue surface
- The posterior pharynx and tonsillar area (Correct answer)
- The inside of the cheek (buccal area)
- The hard palate
Correct answer: The posterior pharynx and tonsillar area
The swab should be rubbed firmly over the posterior pharynx and tonsillar pillars where Group A Streptococcus colonizes, avoiding the tongue and buccal mucosa.
Group A Streptococcus (GAS) preferentially colonizes the posterior pharynx and tonsillar pillars. The swab must be rubbed firmly over these areas, including any areas of redness, swelling, or exudate, to collect adequate organisms for testing. Touching the tongue, buccal mucosa, or lips introduces normal flora that can interfere with the test.
Question 3: What is the proper protocol for labeling a 24-hour urine collection container?
- Patient name only
- Patient name, start date/time, end date/time, and preservative type (Correct answer)
- Just the date and room number
- No label is needed until it reaches the laboratory
Correct answer: Patient name, start date/time, end date/time, and preservative type
A 24-hour urine container must be labeled with the patient's full identification, the exact start and end times of collection, and any preservative added.
24-hour urine collections are timed quantitative tests where accuracy depends on complete collection within the exact timeframe. The container label must include: patient's full name and identification number, the exact start date and time (when the first void was discarded), the scheduled end date and time, and the type of preservative if any.
Question 4: A sputum specimen for culture should ideally be collected at what time?
- After eating lunch
- Early morning before eating or drinking (Correct answer)
- Late evening before bedtime
- Any time during the day
Correct answer: Early morning before eating or drinking
Early morning sputum specimens are preferred because secretions accumulate overnight, yielding a more concentrated sample with higher organism counts.
Early morning sputum collection, before eating, drinking, or oral hygiene, is preferred for several reasons: respiratory secretions accumulate during sleep, providing a concentrated specimen with the highest bacterial load; the cough reflex produces deeper specimens in the morning; and eating or drinking can dilute or contaminate the specimen.
Question 5: Which preservative is typically used in a 24-hour urine collection for vanillylmandelic acid (VMA)?
- Boric acid
- Sodium bicarbonate
- Hydrochloric acid (HCl) (Correct answer)
- No preservative is needed
Correct answer: Hydrochloric acid (HCl)
Hydrochloric acid (HCl) is used as a preservative for VMA collections because it maintains an acidic pH that prevents degradation of catecholamine metabolites.
Vanillylmandelic acid (VMA) is a metabolite of catecholamines (epinephrine and norepinephrine) used to diagnose pheochromocytoma and neuroblastoma. HCl maintains urine pH below 3.0, which stabilizes VMA and other catecholamine metabolites by preventing bacterial degradation and chemical oxidation.
Question 6: A phlebotomist is asked to collect a stool specimen for occult blood testing. What dietary instruction should the patient follow?
- Eat extra red meat for 3 days before collection
- Avoid red meat, NSAIDs, and vitamin C for 3 days prior (Correct answer)
- Fast for 12 hours before specimen collection
- No dietary restrictions are necessary
Correct answer: Avoid red meat, NSAIDs, and vitamin C for 3 days prior
Patients should avoid red meat, NSAIDs, and high-dose vitamin C before fecal occult blood testing to prevent false-positive and false-negative results.
Guaiac-based fecal occult blood tests (gFOBT) detect the peroxidase activity of hemoglobin. Red meat contains animal hemoglobin and myoglobin with peroxidase activity that causes false-positive results. NSAIDs (aspirin, ibuprofen) can cause GI micro-bleeding, also producing false positives. High-dose vitamin C (>250 mg/day) is a reducing agent that can block the oxidation reaction, causing false negatives.
NCCT Non-Blood Specimen Collection 2
Which type of urine specimen is most commonly requested for routine urinalysis?