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| Primary Name |
Partial Thromboplastin Time |
| Synonym |
Activated partial thromboplastin time |
| Synonym |
Activated PTT |
| Contraction |
PTT |
| Contraction |
APTT |
| Contraction |
-- |
| UAB Procedure Number |
2500140 |
| CPT Code |
85730 |
| Specimen |
Collect one (1) blue-stopper tube (3.2% sodium citrate), filled to specified volume. Do not underfill or overfill. |
| Specimen Management |
Centrifuge blue-stopper tube within one ( 1) hour of collection, separate plasma and test or quick-freeze at -70°C. |
| Specimen Accepted |
Daily including weekends |
| Times Available |
All times |
| Test Performed |
All times |
| Available Stat? |
Yes |
| Description |
APTT is performed to monitor unfractionated heparin therapy, detect coagulation inhibitors, and to detect factor deficiencies of the intrinsic and common pathways. Prolonged APTTs in the absence of heparin require APTT mixing studies. The APTT is not valid for monitoring low molecular weight heparin--use the anti-Xa heparin assay. |
| Reference Interval |
25-35 seconds |
| Critical Value |
>100 seconds |
| Therapeutic Range |
*Therapeutic heparin: 71-100 seconds *Prophylactic heparin: 55-70 seconds
Updated 6/21/2007 |
| Follow-up Test |
PTT mixing studies |
| Associated With |
Coagulation factor inhibitors |
| Associated With |
Bleeding disorders |
| Associated With |
Venous thrombosis |
| Associated With |
Heparin therapy |
| Associated With |
Lupus anticoagulant |
| Associated With |
Disseminated intravascular coagulation |
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