A patient's coagulation sample drawn from an IV line shows PT 11.5 seconds, APTT 67 seconds, TT 30 seconds. Which testing step should be performed next?

A patient's coagulation sample drawn from an IV line shows PT 11.5 seconds, APTT 67 seconds, TT 30 seconds. Which testing step should be performed next?

• A. factor assays testing should be performed
• B. a mixing study should be done
• C. a heparin neutralization should be done
• D. an inhibitor assay should be performed

Answer: (C)

When a coagulation panel shows a markedly prolonged APTT and an extended thrombin time in a sample drawn from an IV line, the first step is to neutralize any heparin that may have contaminated the specimen. Heparin in the sample can falsely prolong APTT and TT while leaving PT relatively normal. By using a heparin-neutralizing step (for example, adding protamine or performing a heparinase-treated assay) and rechecking the values, you can determine whether the abnormal results were due to pre-analytical heparin contamination or to a true intrinsic pathway issue. If the results normalize after neutralization, that indicates the interference was due to heparin rather than a factor deficiency or inhibitor. If they remain prolonged even after neutralization, then you would proceed with further testing, such as mixing studies and specific factor or inhibitor assays, to identify the underlying problem.

When a coagulation panel shows a markedly prolonged APTT and an extended thrombin time in a sample drawn from an IV line, the first step is to neutralize any heparin that may have contaminated the specimen. Heparin in the sample can falsely prolong APTT and TT while leaving PT relatively normal. By using a heparin-neutralizing step (for example, adding protamine or performing a heparinase-treated assay) and rechecking the values, you can determine whether the abnormal results were due to pre-analytical heparin contamination or to a true intrinsic pathway issue.

If the results normalize after neutralization, that indicates the interference was due to heparin rather than a factor deficiency or inhibitor. If they remain prolonged even after neutralization, then you would proceed with further testing, such as mixing studies and specific factor or inhibitor assays, to identify the underlying problem.