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Test Name: PTT
Test Code: 1675
Other Names: Partial Thromboplastin Time. Activated, PTT, aPTT
Test Includes: PTT
Specimen Requirements: Plasma
Container: Blue-top (sodium citrate) tube,90% of full draw
Collection Instructions: N/A
Stability: Specimens are stable at room temperature for 24 hours. If testing cannot be completed within 24 hours, specimens should be centrifuged for at least 10 minutes at 1500xg. Plasma should then be transferred to a transfer tube and frozen. Sample is stable when frozen for up to 2 weeks
Rejection Criteria / Special Instructions: Moderate to Gross hemolysis; clotted specimen; frozen specimen thawed in transit; tubes <90% full; improper labeling; specimen collected in tube other than 3.2% citrate
Methodology: Factors of the intrinsic coagulation system are activated by incubating the plasma with optimal amount of phospholipids and a surface activators. The addition of calcium ions triggers the coagulation process and the clotting time is measured.