Laboratory Test Information Guide

Details for Partial Thromboplastin Time (Activated)- PTT

Test Name: Partial Thromboplastin Time (Activated)- PTT
Alternate Name(s): APTT
PTT
Laboratory: Core
Specimen Type: 2.7 mL Blue (3.2% Sodium Citrate) top Vacutainer

Pediatric:

1.8 mL Blue (3.2% Sodium Citrate) top
*In cases where access is difficult, a 0.9 mL Blue top tube is acceptable
Collection Information: Tubes must be filled until vacuum exhausts (until the fill line marked on tube).
Both INR and PTT can be performed on one blue top tube. PTT analysis must be completed within 4 hours of collection.
Requisition: GENERAL LABORATORY REQUISITION
Test Schedule: As required
Turnaround time from when specimen
is received in testing laboratory:
 
Routine
4 hours
Stat
1 hour
 
Reference Range: 0 min - 5 days: 31-54 seconds
5 days - 1 month: 25-60 seconds
1 month - 3 months: 32-55 seconds
3 month - 6 months: 29-50 seconds
6 months - Adult: 20-29 seconds


Therapeutic range for Heparin: 60-85 secs.
Effective Date: 2011-01-14
Revised Date: 2019-04-15
Critical Value: PTT: ≥100 (for patients NOT on anticoagulants)
Interpretive Comments: Detects abnormalities in the Intrinsic pathway. Useful in monitoring heparin therapy.
Special Processing:  
Comments:  
Method of Analysis: Optical clot detection
Critical Information Required:  
Storage & Shipment: Blue (Sodium Citrate) top specimens are kept at 18-24 degrees Celsius.

Samples from patients on therapeutic heparin must be centrifuged within one hour of collection and tested within four hours.

All other samples should be centrifuged and tested within 4 hours of specimen collection.

Samples are discarded after 4 hours.
System Codes: 
Cerner
PTT
 
Referred To:  

Questions? Comments? Contact Laura Gopaul