College of American Pathologists
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Example of patient-specific interpretation for coagulation

October 2001
Michael Laposata, MD, PhD

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The PT is 71.8 seconds and the PTT is 188.5 seconds. There is no evidence for the presence of heparin in the sample. Fibrinogen, which is an acute phase reactant, is markedly elevated at 1121 mg/dL. The PT and PTT remain prolonged in the mixing studies (at time zero and after a one-hour incubation), consistent with an inhibitor. Factor assays reveal <1% factor V. A factor V mixing study is consistent with a factor V inhibitor. The inhibitor interferes with the other factor assays such that a precise level for the other factors cannot be determined.

However, it can be determined that all of the factors (II, VII, IX, X, and XI) are normal, except for factor VIII, which is markedly elevated, and the factor XII level cannot be determined. Factor XII is at least 50%, and even if factor XII is 50%, it can be noted that decreased factor XII does not cause bleeding.

The factor V inhibitor interferes with the lupus anticoagulant assays. As a result, his lupus anticoagulant assays are inconclusive and it is not possible to determine if he also has a lupus anticoagulant.