Coagulation

Thromboplastin-S ISI:1.00

Diagnostic reagent for the in-vitro quantitative determination of prothrombin time (INR) in human plasma in both automatic and manual systems.

Range	Coagulation
Type of specimen	Plasma. The blood should be collected by careful venipuncture and transferred into a tube containing trisodium citrate (0.11 mol/L, 3.2%); mix blood with the anticoagulant at a ratio of 9:1 (4.5 ml blood + 0.5 ml sodium citrate), avoiding foam formation during mixing. For occasional patients with a haematocrit below 20% or above 55%, this ratio must be readjusted to ensure a valid result.
Specimen handling	Centrifuge immediately for 15 minutes at 1500–3000 rpm (approximately 1500 g) and transfer the plasma into a clean test tube; it should be ensured that the plasma is free from platelets. Cap the test tubes to prevent deterioration of samples. Plasma must be tested immediately; if the specimens are held at 2–4 °C they may be tested within 3 hours. Oxalated plasma may induce prolonged clotting times. Due to activation of factor VII by cold, long storage of plasma at 2–8 °C may shorten the PT result; contamination by thromboplastin or haemolysed specimens may also shorten it.
Storage	Thromboplastin-S reagent is ready to use and is stable until the expiry date on the label when properly stored refrigerated at 2–8 °C (do not freeze). Stability: 2 years at 2–8 °C, 1 week at 18–25 °C. The reagent is almost clear; do not use it if it is unusually turbid or contaminated.
Catalogue numbers	5