Is the activated partial thromboplastin time suitable to screen for von Willebrand factor deficiencies?

Abstract

The diagnostic approach to von Willebrand factor deficiencies is challenging and requires discretionary use of laboratory resources. Although extensive preoperative testing is not recommended, the activated partial thromboplastin time may be useful, especially in selected categories of patients. To establish the diagnostic sensitivity of this test to identify isolate von Willebrand factor deficiencies, 204 consecutive patients underwent a routine preoperative screening consisting of activated partial thromboplastin time, von Willebrand factor antigen, intrinsic pathway clotting factors activity, lupus anticoagulants and thrombin time. Thirty-seven patients were diagnosed with haemostasis disturbances other than von Willebrand factor deficiencies and were excluded from the evaluation. Isolated von Willebrand factor deficiency was diagnosed in 11 of the remaining 167 patients. A significant correlation was observed between von Willebrand factor antigen and activated partial thromboplastin time. Receiver operating characteristic curve analysis showed an area under the curve of 0.982 (95% confidence interval: 0.972-0.992; P < 0.001). At the 1.17 upper limit of the activated partial thromboplastin time, sensitivity and specificity were 100 and 85%, respectively, with negative and positive predictive values of 100 and 31%, respectively. These results demonstrate that activated partial thromboplastin time has an excellent diagnostic sensitivity and a satisfactory specificity for identifying isolated von Willebrand factor deficiencies.

Higher morning serum cortisol level predicts increased fibrinogen but not shortened APTT

“…The association between cortisol and von Willebrand factor reported by von Känel et al is not necessary in disagreement with our findings, since APTT is a global coagulation test, which might be shortened not only by elevated levels of von Willebrand factor, but also by an increased activity of a variety of additional coagulation factors, such as VIII, IX and XI [4,5]. Moreover, although reduced levels of von Willebrand factor in plasma produce a prolonged APTT values [6], there is no conclusive evidence that increased levels might be associated with a shortened coagulation time.…”

Validation of a new panel of automated chemiluminescence assays for von Willebrand factor antigen and activity in the screening for von Willebrand disease

“…The diagnosis of VWD requires clinical and laboratory components: a personal history of excessive mucocutaneous bleeding, a family history of excessive bleeding, and a laboratory evaluation. Besides the laboratory screening tests for VWD [closure time with PFA‐100™ (Siemens Healthcare Diagnostics, Marburg, Germany), platelet count and activated partial thromboplastin time (APTT)] more specific assays are required to diagnose VWD . Confirmatory laboratory tests include measurement of FVIII coagulant activity (FVIII:C), the VWF antigen (VWF:Ag), and the activity of the VWF, as up to 30% of cases have a qualitative type 2 defect .…”

A genetic association study of activated partial thromboplastin time in European Americans and African Americans: the ARIC Study

“…von Willebrand disease, caused by vWF deficiency, is a common genetic disease and can prolong the aPTT (21). rs2229446 is a non-synonymous variant of VWF (Arg2185Gln), and its minor allele (T) was associated with lower vWF and factor VIII activity levels in the AA cohort from the NHLBI Exome Sequencing Project (22).…”