PTT, Hepzymed

Abbrev Code:HPTT   
Order Code:LAB3089Order Name:HEPZYMED PTT
Synonyms:Hepzymed Partial Thromboplastin Time
Methodology:Electromagnetic clot detection
CPT Codes: 85730 x1
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 to fill line on the tube
Minimum\Peds Volume:1.8 mL (in 2 mL tube) - filled to fill line on the tube
Container:Blue Na Citrate, 3.2% - fill to fill line on tube
Collection Instructions:If the patient's hematocrit is >55%, contact laboratory to obtain a special tube. If using a butterfly needle, a waste tube must be collected before the blue top.
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 tubes, overfilled tubes, clotted specimens, specimens collected in 3.8% buffered citrate. Specimen greater than 2 hours old or not processed appropriately within 1 hour of collection.

Processing and Shipping

Specimen Processing:Send whole blood or platelet poor plasma. See Associated Link for additional processing instructions.
Shipping Instructions:Ship whole blood specimens at room temperature. Whole blood specimens must be processed within one hour of collection and tested within 2 hours. If greater than1 hour 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 & older 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 of age.
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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