aPTT
aPTT-490
aPTT
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.
Lt blue Sodium citrate (NaCit) - 2.7mL
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.
- Do not over or under fill tube as the ratio of anticoagulant to whole blood is critical
- Immediatley following collection, mix sample by gentle inversion 3 - 4 times to prevent clotting
- Process Platelet Poor Plasma (P.P.P)
- Transfer plasma into an aliquot tube using a spot label "NaCit Plasma P.P.P" to label as platelet poor plasma
- Freeze immediately
Microcentrifuge vial/tube in a Snap cap conical vial/tube and cap (Beaker sites)
Coagulation specimen transport vial/tube (all other sites)
Lt blue Sodium citrate (NaCit) - 2.7mL
Routine:
Frozen (strict)
Refrigerated - NO
STAT:
Ambient
- Patient not on heparin: 4 hours
- Patient on heparin: specimen must be processed within 1 hour of collection, and testing run within 2 hours of collection.
- Improper label (unlabeled or mislabeled)
- Improper anticoagulant
- Improperly filled tube
- Hemolysis
- Clotted specimen
- Delay in transport
- Improper storage/transport temperature
- Patient on heparin > 1.0 IU/mL
Available STAT
Clot Based Assay
0-2 months: 29 - 50 seconds
3-6 months: 28 - 43 seconds
Adult: 28 - 36 seconds
Heparin therapeutic range: 57 - 87 seconds
0 - 28 days of age or outpatient: > 60 seconds