Membrane-based, dry-reagent prothrombin time tests
Zweig, S.E.; Meyer, B.G.; Sharma, S.; Min, C.; Krakower, J.M.; Shohet, S.B.
Biomedical Instrumentation and Technology 30(3): 245-256
1996
ISSN/ISBN: 0899-8205 PMID: 8739001 Document Number: 468965
The authors describe a prototype membrane-based, dry-reagent prothrombin time assay for whole blood. This system uses an asymmetric polysulfone membrane to separate plasma from red blood cells, and works with samples as small as 10 microliters. The membrane contains calcium and thromboplastin, and permits the reactions of the complete extrinsic pathway to occur with minimal distortion from membrane surface interactions. Thrombin generation is monitored optically using a rhodamine-110-based fluorescent thrombin substrate. Fluorescence kinetics are analyzed to produce a prothrombin-time--equivalent parameter that can be converted to an international normalized ratio (INR) value. The system provides results that correlate well with conventional liquid phase prothrombin time assays (R2 = 0.96).