PT/PTT (includes INR)

Alternative Names/Synonyms	APTT, PTT,PTINR
Laboratory	Core Laboratory & Transfusion Medicine
Sub-section	Hematology
Specimen Type	Blood
Test Code	PTPTT

Ordering Instructions, Requisition

MSH Coagulation requisition form (MS 520)

Clinical Significance (If applicable)

See individual test information for PTINR and APTT

Specimen Requirements (Sample Type)

Plasma (3.2% Na Citrate)

Specimen Requirements (Volume (mL))

Full draw

Specimen Requirements (Tube Type)

Light Blue citrate tube
Collection Containers – Tube Types

Draw (mL)

Adult: 2.7 mL
Pediatric Micro tube: 1 mL

Collection Requirements

The 9:1 blood/citrate ratio must be kept constant. Adjustments for the amount of anticoagulant should be made when the hematocrit is abnormal (above 55%). Mix immediately to prevent clotting.
Collection Instructions

Storage / Shipment Details

Send whole blood sample(s) at room temperature as soon as possible.
If specimens cannot be shipped immediately, centrifuge and separate plasma within 1 hour of collection, send frozen plasma on dry ice

Sample Stability

See individual Sample stability for PTINR and APTT

Cause for Rejection

Specimen Acceptability and Transport Guidance

Instrument, Methodology

Automated Coagulation Analyzer

Test Availability

24 hours, 7 days/week.

STAT Turnaround Time

1 hour

Routine Turnaround Time

2 hours

Reference Ranges

See individual ranges and values for PTINR, APTT In case of discrepancies, always interpret results using reference ranges as stated on laboratory reports and/or electronic patient chart.

Laboratory Contact Information

416-586-4800 Extension 4688

Special Instructions

Must indicate anticoagulant status