The activated partial thromboplastin time (aPTT) test is a screening procedure used primarily to determine deficiencies in factors necessary for the formation of intrinsic prothrombin activator, namely factors VIII, IX, XI and XII.
Factors II, V and X deficiencies (normally detected by the prothrombin time) can also be detected by the aPTT.
The test will not detect platelet disorders, isolated factor XII and factor XIII deficiencies.
Do not over or under fill tube as the ratio of anticoagulant to whole blood is critical
If the patient has a hematocrit >55, a specially prepared Lt blue Sodium citrate (NaCit) tube must be used in place of the standard Lt blue Sodium citrate (NaCit) tube.
Process Platelet Poor Plasma (P.P.P) following the linked instructions.
STAT requests only:
Send whole blood sample in original collection container with STAT courier.
Must be tested within 4 hours of collection.
Refrigerated - NO
Coagulation test method
0-2 months: 29 - 50 seconds
3-6 months: 28 - 43 seconds
Adult: 25 - 36 seconds
Heparin therapeutic range: 76 - 99 seconds
0 - 28 days of age or outpatient: > 60 seconds