Partial thromboplastin time: Difference between revisions
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In | In [[hematology],] the '''partial thromboplastin time (PTT)''' is "the time required for the appearance of [[fibrin]] strands following the mixing of plasma with phospholipid platelet substitute (e.g., crude cephalins, soybean phosphatides). It is a test of the [[intrinsic pathway]] ([[factor VIII|factors VIII]], [[factor IX|IX]], [[factor XI|XI]], and [[factor XII|XII]]) and the [[common pathway]] ([[fibrinogen]], [[prothrombin]], [[factor V|factors V]] and [[factor X|X]]) of blood [[coagulation]]. "<ref>{{MeSH}}</ref> It is used as a screening test and to monitor [[anticoagulant]] therapy. | ||
Both the PTT and the [[prothrombin time]] (PT) are subject to variation due both to the specific batches of reagents, and to laboratory methods. A calculation involving both the PT and PTT, called the [[International Normalized | Both the PTT and the [[prothrombin time]] (PT) are subject to variation due both to the specific batches of reagents, and to laboratory methods. A calculation involving both the PT and PTT, called the [[International Normalized Ratio]] (INR), corrects for the variability and is the more useful value for monitoring. When the PT or PTT sugggests an error in coagulation, more detailed studies become appropriate. | ||
==References== | ==References== | ||
<references/> | <references/> | ||
Revision as of 09:43, 23 August 2010
In [[hematology],] the partial thromboplastin time (PTT) is "the time required for the appearance of fibrin strands following the mixing of plasma with phospholipid platelet substitute (e.g., crude cephalins, soybean phosphatides). It is a test of the intrinsic pathway (factors VIII, IX, XI, and XII) and the common pathway (fibrinogen, prothrombin, factors V and X) of blood coagulation. "[1] It is used as a screening test and to monitor anticoagulant therapy.
Both the PTT and the prothrombin time (PT) are subject to variation due both to the specific batches of reagents, and to laboratory methods. A calculation involving both the PT and PTT, called the International Normalized Ratio (INR), corrects for the variability and is the more useful value for monitoring. When the PT or PTT sugggests an error in coagulation, more detailed studies become appropriate.
References
- ↑ Anonymous (2024), Partial thromboplastin time (English). Medical Subject Headings. U.S. National Library of Medicine.