Laboratory Services

PTT (Partial Thromboplastin Time)

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Updated Test Information:

Test Description
PTT (Partial Thromboplastin Time)
Synonym(s)

PTT, APTT

Test ID
PTT
General Information

Used to monitor treatments with thrombin inhibitors and during heparin or oral anticoagulant therapy


Interference: When monitoring heparin therapy, any release of platelet factor 4 (PF4) which is a potent inhibitor of heparin, represents a major source of error

Specimen Type

Plasma

Specimen Requirements

Light Blue
Aliquot Tube

Specimen Collection / Processing Instructions

Light Blue - Centrifuge immediately, transfer plasma to aliquot tube and freeze at less than -20°C.

Minimum Sample Volume

The sodium citrate collection tube must be filled to 90% of capacity.

Pediatric Min. Volume (if applicable)

The sodium citrate collection tube must be filled to 90% of capacity.

Additional Processing Details

If specimen will be received >4 hours after collection, centrifuge for 15 minutes at 2000-2500g. Transfer the plasma to an aliquot tube and store frozen at ≤ -20°C. DO NOT store plasma at 2° - 8°C

Stability

Plasma Na Citrate
  - Frozen (preferred): 14 days
  - Room Temperature: 4 hours
  - Refrigerated: Unacceptable


Unspun Whole Blood in Na Citrate
 -Room temperature: 4 hours
 -Refrigerated: Unacceptable
 -Frozen: Unacceptable

Unacceptable Specimen Conditions

Refrigerated specimen; Quantity not sufficent; improperly labeled specimens; specimens not collected in 3.2% buffered sodium citrate tube; clotted specimens; under or over filled specimen tubes; severe hemolysis; improperly labeled specimens

Methodology

Automated

Estimated TAT

0-2 days

Testing Schedule

Monday-Saturday, & STAT

CPT Code(s)

85730

Reference Range

25.1-38.9 seconds

Reflex Conditions

None

Performing Lab

Incyte Diagnostics

LOINC Code(s)

14979-9