Laboratory suggestion. Interpretation of plasma protamine paracoagulation test

The reliability of the plasma protamine paracoagulation test has been questioned because of the controversy surrounding its interpretation and because of false positives reported with high frequency in some series. To minimize the frequency of false positives, it is recommended that when the test is done at room temperature, clot or fibrin strand formation be considered a positive result and precipitates be considered negative. Use of the wire hook to distinguish fibrin strands from precipitates is suggested. Nascent clotting and blood drawn from indwelling catheters should be avoided.