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Test Code LAB325 Activated Partial Thromboplastin Time

Performing Lab

Arnot Ogden Medical Center / Ira Davenport Memorial Hospital

Ordering Recommendations

Monitoring heparin therapy (unfractionated heparin).

Screening for certain coagulation factor deficiencies.

Detection of coagulation inhibitors such as lupus anticoagulant, specific factor inhibitors, and nonspecific inhibitors.

Collect

Citrated Plasma

Collection Device

Sodium Citrate Blue Top Tube

Minimum Requirements

FULL BLUE TOP TUBE.

Unacceptable Conditions

Hemolyzed, clotted, short draw or overfilled specimens are not acceptable and must be redrawn.

Collection Instructions

*Must be spun and separated within 4 hours of collection.

  • Blue top tubes should NOT be the first tube drawn.
  • Tubes should be allowed to fill until the vacuum is exhausted and blood flow ceases.  

Pediatric Collection

Contact laboratory for pediatric draws.

Stability (from collection to initiation)

Room Temp

 4 Hours
Refrigerated 4 Hours
Frozen 14 Days*

*Sample must be centrifuged and decanted within 4 hours of draw.

Storage/Transport Temperature

Room temperature, Refrigerated, or Spun, Separated and Frozen*

Remarks

TURN AROUND TIME

STAT

 1 Hour
Routine 8 Hours

Synonyms

PTT

Methodology

Turbidimetric

 

Start Date

9/13/2017

Last Review Date

6/24/2025

7/3/25 AP

7/31/2025 JLH