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K W von Pape

Publications and source records attributed to K W von Pape.

4 recordsLinked to original sources
PubMed2000

Platelet function analysis with PFA-100 in patients medicated with acetylsalicylic acid strongly depends on concentration of sodium citrate used for anticoagulation of blood sample.

Our data from 214 patients after cessation of long-term therapy with 100 mg/d ASA demonstrate that the determination of platelet-related primary hemostasis in citrated whole blood with PFA-100 is a reliable and sensitive method for the detection of ASA-induced platelet dysfunction. However, the sensitivity of the method is strongly dependent on concentration of sodium citrate used as anticoagulant. The results of PFA-100 testing show a clearly enhanced sensitivity for ASA when blood samples were collected with 0.129 M rather than 0.106 M sodium citrate. According to sample stability, PFA-100 results can only be confirmed up to 1 hour postcollection when blood was anticoagulated with 0.129 M but not with 0.106 M sodium citrate. Therefore, we recommend that testing with PFA-100 in patients with suspected ASA-induced platelet dysfunction should be performed exclusively in blood collected in buffered 0.129 M sodium citrate.

Artifacts↗
PubMed1994

Thrombin-based antithrombin assays show overestimation of antithrombin III activity in patients on heparin therapy due to heparin cofactor II influence.

An extensive comparison has been performed on the clinical chemistry automate Hitachi 717 between thrombin- and Factor Xa-based methods for determination of antithrombin III activity. In 460 patients who did not receive any heparin therapy the agreement between assays was in general close although the thrombin-based methods resulted in slightly higher assignments of 0.3-2.6% antithrombin III activity. The discrepancy was, however, substantial in plasmas from patients receiving heparin of > or = 20000 IU/day, resulting in plasma levels of heparin of 0.8-1.2 IU/ml. Thus, analysis of 102 patients showed that the thrombin-based methods resulted in, on average, 7-16% higher assignment of antithrombin III activity as compared to the Factor Xa-based method used. Addition of antibodies to antithrombin III and heparin cofactor II revealed that the discrepancy was primarily due to contribution of heparin cofactor II activity in the thrombin-based methods. The results thus suggest that the Factor Xa-based antithrombin III activity method provides more valid results in patients on heparin therapy.

Antithrombin III↗