PCT Lab Procedures 2 — Questions and Answers
Question 1: When collecting a urine specimen for culture and sensitivity, which technique is most critical?
- Use a clean-catch midstream method (Correct answer)
- Collect the first morning void in any container
- Refrigerate the specimen for 24 hours before sending
- Add preservative tablets immediately after collection
Correct answer: Use a clean-catch midstream method
Clean-catch midstream technique minimizes contamination from skin flora, ensuring accurate culture results.
Question 2: A PCT notices a blood specimen tube has hemolysis. What does this indicate?
- The sample is ready for analysis
- Red blood cells have ruptured, potentially affecting results (Correct answer)
- The tube was filled correctly
- The specimen needs to be refrigerated immediately
Correct answer: Red blood cells have ruptured, potentially affecting results
Hemolysis occurs when red blood cells break open, releasing their contents and interfering with many lab tests.
Question 3: Which additive is found in a light blue (citrate) tube and what is it primarily used for?
- EDTA; used for CBC testing
- Sodium citrate; used for coagulation studies (Correct answer)
- Heparin; used for chemistry panels
- Sodium fluoride; used for glucose testing
Correct answer: Sodium citrate; used for coagulation studies
Light blue tubes contain sodium citrate, which chelates calcium to prevent clotting and is used for PT and aPTT coagulation tests.
Question 4: What is the correct angle for inserting the needle during a standard venipuncture?
- 5–10 degrees
- 15–30 degrees (Correct answer)
- 45–60 degrees
- 90 degrees
Correct answer: 15–30 degrees
A 15–30 degree angle allows the needle to enter the vein cleanly without passing through the posterior wall.
Question 5: A patient's fasting glucose level is 126 mg/dL on two separate occasions. This finding is consistent with:
- Normal fasting glucose
- Prediabetes
- Diabetes mellitus (Correct answer)
- Hypoglycemia
Correct answer: Diabetes mellitus
A fasting glucose ≥126 mg/dL on two separate tests meets the diagnostic criterion for diabetes mellitus.
Question 6: Which specimen is MOST appropriate for detecting occult blood in stool?
- A random urine sample
- A fecal immunochemical test (FIT) card (Correct answer)
- A throat swab
- A venous blood draw in a red-top tube
Correct answer: A fecal immunochemical test (FIT) card
The fecal immunochemical test (FIT) is the standard method for detecting hidden (occult) blood in stool samples.
Question 7: When using a lancet for capillary blood collection, which site is preferred for an adult patient?
- The earlobe
- The fingertip (lateral aspect) (Correct answer)
- The heel
- The forearm
Correct answer: The fingertip (lateral aspect)
The lateral aspect of the fingertip provides adequate blood flow and avoids bone and nerve damage in adults.
PCT Lab Procedures 2
When collecting a urine specimen for culture and sensitivity, which technique is most critical?