Blood Ammonia Testing Procedures

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Questions and Answers

What should be done to a whole blood ammonia specimen to prevent ammonia level increase before testing?

Place in an ice slurry (correct)

Store at room temperature

Send to the lab immediately

Keep in a dark location

How quickly should a serum or plasma specimen be centrifuged after collection to avoid altered analyte levels?

Within 12 hours

Within 2 hours (correct)

Within 6 hours

Within 30 minutes

What is the maximum time EDTA whole blood tubes can be stored at room temperature without affecting test results?

72 hours

24 hours (correct)

12 hours

48 hours

What happens to glucose levels in uncentrifuged blood if left standing at room temperature?

Decline by 5% to 7% per hour Signup and view all the answers

For how long can serum and plasma specimens safely remain at room temperature before test results could be adversely affected?

8 hours Signup and view all the answers

What should be done with plasma or serum specimens if testing is not completed within 8 hours?

Refrigerate at 2-8°C Signup and view all the answers

What is crucial when thawing frozen specimens before testing?

Thaw only once Signup and view all the answers

Which of the following test results can be negatively affected by light exposure?

Vitamin B12 and bilirubin Signup and view all the answers

What could happen if a serum specimen is held for more than two hours before centrifugation?

Some analyte levels may be falsely decreased. Signup and view all the answers

Why is it essential to remove serum from red blood cells after centrifugation?

To prevent loss of potassium into serum. Signup and view all the answers

What is a key issue with using a pneumatic tube system for laboratory specimens?

It may cause damage to red blood cells. Signup and view all the answers

Which test is affected by pneumatic tube system transport?

Potassium Signup and view all the answers

What is the recommended time for a specimen to clot before centrifugation?

30 minutes Signup and view all the answers

What can improper balance of the centrifuge result in?

Mechanical centrifuge damage. Signup and view all the answers

How long should a specimen be transported using a pneumatic tube system?

2 hours maximum Signup and view all the answers

What type of pouch is required for urine specimens sent via pneumatic tube?

Biohazard bags Signup and view all the answers

What should you ensure about the carrier used for transporting specimens?

It is clean and free from cracks. Signup and view all the answers

What happens if centrifugation speed is increased too much?

It can cause hemolysis. Signup and view all the answers

What is the effect of incomplete clotting in serum specimens?

Interference from fibrin residue. Signup and view all the answers

Which of the following tests is NOT affected by pneumatic tube transport?

Sodium Signup and view all the answers

What should be checked before a specimen is sent through a pneumatic tube system?

The integrity of the carrier. Signup and view all the answers

What happens to glucose levels if there is a delay in centrifugation?

Glucose levels may be falsely decreased. Signup and view all the answers

Study Notes

Blood Ammonia and Specimen Handling

Blood ammonia levels rapidly increase at room temperature due to amino acid breakdown; therefore, a specimen must be placed in ice slurry and transported quickly to the lab.
Whole blood samples should be separated from cells and tested promptly to avoid altered analyte levels or hemolysis.
Serum or plasma specimens should be centrifuged within two hours of collection to prevent changes in serum constituents.

Impact of Storage Conditions

Prolonged contact with cells can falsely alter analyte levels (e.g., increased potassium and decreased glucose).
Specimens stored at room temperature (20-25°C) can adversely affect test results; serum/plasma should be refrigerated at 2-8°C if testing is delayed, especially beyond eight hours.
Freezing specimens should be limited to once to prevent analyte deterioration, particularly for tests affected by repeated freeze-thaw cycles.

Light Sensitivity of Specimens

Light-sensitive tests include Vitamin B12, bilirubin, beta carotene, and folate; these should be collected in amber tubes or wrapped in aluminum foil.
Tests like Hemoglobin, Hematocrit, and aPTT are unaffected by light exposure.

Effects of Time on Analytes

Glucose levels decrease by 5% to 7% per hour in uncentrifuged blood at room temperature; timely separation is essential.
Different analytes may be subject to cellular consumption or release into the serum, skewing results if centrifugation is delayed beyond two hours.

Pneumatic Tube System Transport Protocol

Transport protocols for laboratory specimens via pneumatic tube system must ensure specimen integrity and safety.
Tests negatively impacted by pneumatic tube transport include potassium and lactate dehydrogenase, while others like albumin and creatinine are not affected.

Specimen Collection and Clotting

Non-additive specimens should clot for at least 30 minutes before centrifugation to avoid fibrin residue that can affect testing.
Improper centrifugation, either due to speed or incomplete clotting, can lead to hemolysis or residual gel particles, interfering with test accuracy.

General Recommendations

Compliance with standard specimen handling procedures prevents issues such as contamination, hemolysis, and inaccurate test results.
Proper specimen storage and timely processing are critical to maintaining the integrity of lab results and ensuring patient safety.

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Description

This quiz covers the best practices for handling blood ammonia specimens to ensure accurate test results. It highlights the importance of rapid processing and temperature control during collection and transport. Understand the protocols for managing serum and plasma samples to avoid alterations in analyte levels.