For PTT samples when GT is indicated, how long are they good?

For PTT samples when GT is indicated, how long are they good?

• A. 8 hours
• B. 1 hour
• C. 24 hours
• D. 12 hours

Answer: (A)

When a GT indication is noted for a PTT sample, the test results rely on the sample staying stable long enough for accurate measurement. Coagulation factors and related components can degrade or change with time at room temperature, which can make the PTT reading unreliable. Limiting the testing to eight hours helps ensure the intrinsic pathway factors are still representative of the patient’s physiology and not affected by pre-analytical changes. That’s why eight hours is the best choice. Shorter windows like one hour wouldn’t capture typical clinical workflows, and longer windows such as twelve or twenty-four hours increase the risk of drift in factor activity and inaccurate results.

When a GT indication is noted for a PTT sample, the test results rely on the sample staying stable long enough for accurate measurement. Coagulation factors and related components can degrade or change with time at room temperature, which can make the PTT reading unreliable. Limiting the testing to eight hours helps ensure the intrinsic pathway factors are still representative of the patient’s physiology and not affected by pre-analytical changes. That’s why eight hours is the best choice. Shorter windows like one hour wouldn’t capture typical clinical workflows, and longer windows such as twelve or twenty-four hours increase the risk of drift in factor activity and inaccurate results.