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HelpTest Code PTT Partial Thromboplastin Time (PTT), Plasma
Methodology
Photometric, Sensitive Synthetic Reagent (SynthASilTM
APTT Reagent)
Useful for monitoring heparin therapy, coagulation screening, liver
failure, and disseminated intravascular coagulation.
Performing Laboratory
St. Clair Hospital Laboratory
Specimen Requirements
1 light blue-top (3.2% sodium citrate) tube (0.3 mL of sodium
citrate plasma) drawn as follows:
1. If patient is on heparin or Coumadin®, centrifuge whole
blood, separate, freeze plasma immediately, and send specimen
frozen in plastic vial. If unable to spin and freeze, send whole
blood at ambient temperature immediately to the lab.
Do not refrigerate.
2. If patient is not on anticoagulants, send whole blood unspun at
ambient temperature. This type of specimen is stable for at least 8
hours.
Note: If multiple tubes are being drawn,
see “Order of Draw Instructions”
in “Specimen Collection, Preparation, and
Transport” in “General Information.”
Reference Values
23-36 seconds
Critical value (automatic call-back): >150 seconds
Day(s) Test Set Up
Monday through Sunday