ASCP Specimen Collection 2 — Questions and Answers
Question 1: What is the maximum depth for a heel stick on a newborn infant?
- 1.0 mm
- 2.0 mm (Correct answer)
- 3.0 mm
- 4.0 mm
Correct answer: 2.0 mm
The maximum penetration depth for a newborn heel stick is 2.0 mm to avoid puncturing the calcaneus and causing osteomyelitis.
CLSI guidelines specify that heel puncture depth should not exceed 2.0 mm in newborns. The calcaneus is only 2.0-2.4 mm below the skin surface at the posterior heel. Only CLSI-approved incision devices designed for neonatal use should be used. Puncture sites should be on the medial or lateral plantar surface of the heel.
Question 2: When collecting a timed specimen such as a cortisol level, what is the most critical factor?
- Using the correct tube color
- Drawing the specimen at the exact specified time (Correct answer)
- Filling the tube to the marked line
- Using a butterfly needle for accuracy
Correct answer: Drawing the specimen at the exact specified time
Timed specimens must be collected at the exact time specified because many analytes like cortisol follow circadian rhythms.
Cortisol peaks in early morning (6-8 AM) and reaches its lowest point around midnight. A cortisol drawn at the wrong time cannot be properly interpreted. Other timed specimens include therapeutic drug monitoring (peak and trough levels), glucose tolerance tests, and serial cardiac troponin draws.
Question 3: Which specimen type requires cold agglutinin precautions during collection and transport?
- Routine CBC
- Cold agglutinin titer (Correct answer)
- Blood culture
- Lipid panel
Correct answer: Cold agglutinin titer
Cold agglutinin specimens must be kept warm (37 degrees C) because cold agglutinins cause red blood cells to clump at lower temperatures.
Cold agglutinins are IgM antibodies that cause RBC agglutination below 37 degrees C. The collection tube should be pre-warmed, the specimen collected into the warm tube, and transported in a 37 degree container. If the specimen cools, cold agglutinins bind to RBCs and are consumed, producing falsely decreased titer results.
Question 4: What is the correct procedure for collecting a midstream clean-catch urine specimen?
- Collect the first portion of urine into the specimen cup
- Clean the genital area, begin voiding into the toilet, then collect midstream urine (Correct answer)
- Collect all urine passed during the void
- Use a catheter for all clean-catch specimens
Correct answer: Clean the genital area, begin voiding into the toilet, then collect midstream urine
A midstream clean-catch requires cleaning the area, beginning to void into the toilet to flush bacteria, then collecting the midstream portion in a sterile container.
The clean-catch technique minimizes contamination from normal flora. Steps: wash hands, clean periurethral area with antiseptic, begin voiding into toilet (initial stream flushes bacteria), collect 30-60 mL midstream without stopping flow, cap without touching the inside, and transport within 2 hours or refrigerate.
Question 5: A glucose tolerance test (GTT) requires fasting. How long must the patient fast before the test?
- 4-6 hours
- 8-12 hours (Correct answer)
- 16-20 hours
- 24 hours
Correct answer: 8-12 hours
Patients must fast 8-12 hours before a glucose tolerance test to establish a valid baseline fasting glucose level.
The OGTT requires 8-12 hours fasting (10-12 hours optimal). Only water is permitted. The test involves drawing fasting blood, having the patient drink 75g glucose (adults), then collecting specimens at timed intervals. Fasting less than 8 hours elevates baseline glucose; fasting more than 16 hours can cause reactive hypoglycemia.
Question 6: Which specimen requires protection from light during transport to the laboratory?
- Complete blood count specimen
- Bilirubin specimen (Correct answer)
- Basic metabolic panel
- Urinalysis specimen
Correct answer: Bilirubin specimen
Bilirubin is a photosensitive compound that degrades when exposed to light, resulting in falsely decreased levels.
Bilirubin undergoes photoisomerization and photo-oxidation when exposed to light, producing falsely decreased results. Specimens must be wrapped in aluminum foil or placed in amber containers immediately after collection. This is particularly important for neonatal bilirubin specimens. Other light-sensitive analytes include vitamins A, B6, B12, folate, and porphyrins.
ASCP Specimen Collection 2
What is the maximum depth for a heel stick on a newborn infant?