Free NPA Laboratory Practices & Specimen Handling Questions and Answers — Questions and Answers
Question 1: What is the correct procedure for handling blood specimens?
- Store blood specimens at room temperature
- Refrigerate blood specimens immediately (Correct answer)
- Store blood specimens in a freezer
- Leave specimens exposed to light
Correct answer: Refrigerate blood specimens immediately
Many blood specimens, especially those for chemistry or hematology tests, need to be refrigerated immediately after collection and processing (if applicable) to preserve their integrity. Refrigeration slows down metabolic processes and degradation of analytes, ensuring accurate test results. However, specific temperature requirements can vary by test type.
Question 2: What is the primary reason for properly labeling blood specimens?
- To keep the laboratory clean
- To ensure proper test analysis (Correct answer)
- To speed up the testing process
- To reduce costs for the laboratory
Correct answer: To ensure proper test analysis
Proper labeling of blood specimens is critical for patient safety and accurate diagnosis. Each specimen must be clearly labeled with the patient's full name, date of birth, date and time of collection, and the phlebotomist's initials. This ensures the correct specimen is matched with the correct patient and ordered tests, preventing misidentification errors that could lead to severe medical consequences.
Question 3: What is the best practice for transporting specimens to the laboratory?
- Use the quickest method possible, regardless of temperature
- Transport specimens in a biohazard bag with appropriate refrigeration (Correct answer)
- Transport specimens at room temperature in an open container
- Transport specimens without any protective packaging
Correct answer: Transport specimens in a biohazard bag with appropriate refrigeration
Blood specimens must be transported safely and under controlled conditions to maintain their integrity and prevent contamination. Using a biohazard bag protects against leaks and identifies the contents as hazardous, while appropriate refrigeration (or other temperature control) prevents degradation of analytes. This ensures accurate test results and protects transport personnel from potential exposure.
Question 4: What should be done if a blood specimen is clotted?
- Discard the specimen immediately
- Refrigerate it before re-collecting (Correct answer)
- Test the sample anyway
- Add more blood to the specimen
Correct answer: Refrigerate it before re-collecting
If a blood specimen is clotted when it shouldn't be (e.g., in an anticoagulant tube), it indicates an issue with collection or mixing, and the sample is unsuitable for many tests. The correct procedure is to refrigerate the clotted specimen to preserve it while a new, properly collected specimen is obtained. The clotted sample cannot be used for tests requiring whole blood or plasma.
Question 5: How can contamination of a blood specimen be prevented?
- By using a separate needle for each patient
- By properly cleaning the site before blood collection (Correct answer)
- By avoiding gloves during specimen collection
- By reusing needles after sterilization
Correct answer: By properly cleaning the site before blood collection
Contamination of a blood specimen, particularly with skin flora, can lead to inaccurate test results, especially for blood cultures. Properly cleaning the venipuncture site with an antiseptic before the draw significantly reduces the presence of microorganisms on the skin. This ensures the collected blood is representative of the patient's internal state and prevents false positive results.
Question 6: What is the correct way to handle a blood specimen that has been exposed to extreme temperatures?
- Allow the specimen to warm up to room temperature before testing (Correct answer)
- Freeze the specimen to preserve it
- Discard the specimen immediately
- Heat the specimen to a boiling point
Correct answer: Allow the specimen to warm up to room temperature before testing
Blood specimens exposed to extreme temperatures can undergo cellular damage or analyte degradation, affecting test accuracy. If a specimen has been frozen, it should be allowed to thaw completely and gently mix to room temperature before testing. However, severe temperature excursions often necessitate recollection as the integrity may be permanently compromised.
Question 7: How should blood specimens be stored for long-term preservation?
- In a warm, dry place
- In a refrigerated area or a freezer for long-term storage (Correct answer)
- In direct sunlight to prevent bacterial growth
- At room temperature in an open container
Correct answer: In a refrigerated area or a freezer for long-term storage
For long-term preservation, blood specimens (or components like plasma/serum) are typically stored in a freezer, often at -20°C or -80°C, to halt degradation processes. Short-term storage usually involves refrigeration (2-8°C). Proper temperature control is crucial to maintain the stability of analytes and cellular components for future testing or research, ensuring reliable results over time.
Question 8: What is the purpose of using anticoagulants in blood specimens?
- To preserve blood plasma for testing (Correct answer)
- To reduce the volume of blood collected
- To improve the color of the blood sample
- To increase blood flow during collection
Correct answer: To preserve blood plasma for testing
Anticoagulants are substances that prevent blood from clotting. In blood specimens, their purpose is to keep the blood in a liquid state, allowing for the separation of plasma or serum, which is then used for various diagnostic tests. This preservation ensures that the cellular components do not interfere with the analysis of the liquid portion of the blood.
Question 9: What is the role of specimen handling in ensuring the accuracy of test results?
- Proper handling ensures accurate and reliable test results (Correct answer)
- Specimen handling does not affect test accuracy
- Specimen handling only affects the timing of test results
- Incorrect handling can sometimes improve test accuracy
Correct answer: Proper handling ensures accurate and reliable test results
Proper specimen handling is crucial for maintaining the integrity and quality of blood samples. Incorrect handling, such as improper temperature, delayed processing, or inadequate mixing with anticoagulants, can degrade analytes or cause hemolysis. This degradation can lead to inaccurate or unreliable test results, potentially affecting patient diagnosis and treatment.
Free NPA Laboratory Practices & Specimen Handling Questions and Answers
What is the correct procedure for handling blood specimens?