Activated Partial Thromboplastin Time
Test Mnemonic
PTT
CPT Codes
- 85730 - QTY (1)
LOINC ®
14979-9
Aliases
- Activated Partial Thromboplastin Time
- APTT
- Partial Thromboplastin Time
Performing Laboratory
Cleveland Clinic Laboratories
Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 1 mL | Plasma | Sodium citrate (Lt. Blue) | Centrifuge, aliquot and freeze ASAP. | Collection tube must be filled to total fill volume. Inadequately filled tubes will be rejected. NonTesting Sites: Centrifuge, aliquot platelet poor plasma into a separate tube with Epic Beaker label, freeze plasma at -20C, send frozen plasma to Main Campus on dry ice. | |
| 1.8 mL | Whole blood | Sodium citrate (Lt. Blue) | Centrifuge, aliquot and freeze ASAP. | Collection tube must be filled to total fill volume. Inadequately filled tubes will be rejected. NonTesting Sites: Centrifuge, aliquot platelet poor plasma into a separate tube with Epic Beaker label, freeze plasma at -20C, send frozen plasma to Main Campus on dry ice. |
Minimum Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| N/A | Collection tube must be filled to total fill volume. Inadequately filled tubes will be rejected. |
Stability
| Environmental Condition | Description |
|---|---|
| Ambient | 4 hours |
| Refrigerated | Unacceptable |
| Frozen | 14 days at -20 C; 6 months at -70 C |
Days Performed
Sun - Sat
Turnaround Time
8 hours
Methodology
| Name | Description |
|---|---|
| Automated Optical Clot Detection |
Reference Range
| Activated PTT | |||||
|---|---|---|---|---|---|
| Sex | Age From | Age To | Type | Range | Range Unit |
| Days | 1 Days | Normal | 27.1 - 43.7 | sec | 2 Days | 5 Days | Normal | 22.0 - 48.0 | sec | 6 Days | 30 Days | Normal | 22.1 - 44.3 | sec | 1 Months | 3 Months | Normal | 20.8 - 40.2 | sec | 4 Months | 11 Months | Normal | 24.3 - 34.4 | sec | 1 Years | 99 Years | Normal | 23.0 - 32.4 | sec | Years | 99 Years | Urgent | > 100.0 | sec | Years | 99 Years | Critical | EXTREMELY ABNORMAL RESULT. No clot detected at 320 seconds. Refer to anticoagulation nomogram for further actions. |
Special Info
Collection tube must be filled to total fill volume. Inadequately filled tubes will be rejected. Specimens with hematocrit values > 55% have spuriously increased APTT values. To correct for this, specimens should be re-collected using a specified whole blood to sodium citrate ratio. Contact the performing lab for specific instructions.
Clinical Info
Evaluation of hemostasis.