Activated Partial Thromboplastin Time (APTT / aPTT / PTT) Test Procedure

Principle      Platelet-poor plasma is added to an equal volume of partial thromboplastin reagent and warmed to 37°C for an exact incubation time. Pre-warmed (37°C) calcium chloride reagent (0.025M) is added to this mixture to activate the coagulation cascade. The time required for clot formation is recorded. Clot...

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Thrombin Time (TT) Test

     TT has an important role as a screening test because it measures the conversion of fibrinogen to fibrin by adding excess thrombin to undiluted plasma. Because the additional clotting factors previously measured in the PT and APTT have no effect on this test, TT is generally useful for evaluating other parameters...

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Qualitative D-Dimer Test

Principle      D-dimer is a fibrin fragment that results when plasmin acts on cross-linked fibrin in the presence of factor XIII. D-dimers are produced from an insoluble fibrin clot. Available since the 1990s, this semiquantitative assay provides evidence of normal or abnormal levels of D-dimer. Latex particles are...

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Prothrombin Time (PT) Manual Test Procedure

Principle      The addition of pre-warmed (37°C) platelet-poor plasma to thromboplastin-calcium reagent activates the coagulation cascade at Factor VII. The time required for clot formation is recorded. Clot formation may be detected by optical or electromechanical methods using manual, semi-automated, or automated...

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Hemacytometer

          Cell counts are performed manually by diluting blood with a diluent, loading a small amount of the diluted sample on a ruled device (hemacytometer), and counting the cells microscopically. The hemacytometer consists of two side-by-side identically ruled glass platforms mounted in a glass holder....

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Anticagulants

Most tests performed in the hematology laboratory involve anticoagulated blood. Once the blood has left the body, a series of reactions occurs causing blood to clot within minutes. To prevent coagulation from occurring, a substance called an anticoagulant is mixed with the blood. Three anticoagulants are used in the hematology laboratory:- Ethylenediaminetetraacetic...

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Sickle Cell Screening Procedure

v\:* {behavior:url(#default#VML);} o\:* {behavior:url(#default#VML);} w\:* {behavior:url(#default#VML);} .shape {behavior:url(#default#VML);} Principle:-      The sickle screen kit provides a procedure based on hemoglobin solubility. Hemoglobin S is insoluble when combined with a buffer and a reducing agent. This occurs when...

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