PTT, Hepzymed

Sunquest Code:HPTT  
Epic Code:LAB3089Epic Name:HEPZYMED PTT
Synonyms:Hepzymed Partial Thromboplastin Time
Methodology:Electromagnetic clot detection
CPT Code:85730
Turnaround Time:Performed and reported 24 hours/day.
Associated Links:

Specimen Collection and Processing for Coagulation Specimens

Collection Instructions

Optimal Volume:2.7 mL (in 3 mL tube) - filled as vacuum will allow or to fill line on the tube
Minimum\Peds Volume:1.8 mL (in 2 mL tube) - filled as vacuum will allow or to fill line on the tube
Collection Instructions:Do not use the first 2 mL of blood collected. For correct anticoagulant to blood ratio, place 2.7 mL blood in 3 mL tube or 1.8 mL blood in 2 mL tube. If the patient's hematocrit is >55%, contact laboratory to obtain a special tube.
After Care:If the patient has a coagulation abnormality, apply direct pressure to the puncture site for 10 minutes; apply a pressure dressing. Instruct the patient to leave the bandage on for 12 hours.
Causes for Rejection:Underfilled tube; clotted specimen; refrigerated specimen; overfilled tubes.

Processing and Shipping

Specimen Processing:Send whole blood or platelet poor plasma. See Associated Link for additional processing instructions.
Shipping Instructions:Ship at room temperature. Whole blood specimens must arrive within 4 hours. If greater than 4 hours is required for transport, follow specimen processing instructions and ship frozen plasma on dry ice.
Test Performed at or Referral Lab Coagulation  (UMMC/UMMCH-West Bank)


Critical Range:Greater than 105 seconds.
Reference Range:

6 months of age and greater

22-37 seconds

Less than 6 months of age

Pediatric specific ranges have not been established; however the PTT normal range is higher in children less than 6 months old.



Use:Hepzymed PTT is helpful for evaluation of prolonged PTT. Heparinase I cleaves heparin at multiple sites per molecule. The cleaved heparin fragments are inactive without any antithrombotic activity. After treatment with hepzyme, PTT can be assayed. Dade Hepzyme can be used to rule out heparin contamination as responsible for an abnormal PTT result, compare the PTT results for heparinized samples when monitoring heparin therapy, and evaluate patients on combined heparin and warfarin therapy. Hepzymed PTT determines whether contamination is responsible for a prolonged PTT. If hepzyme PTT is normal, heparin contamination caused the PTT prolongation. If hepzymed PTT remains prolonged, a lupus inhibitor work-up is recommended.

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