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Test Code 607 Reptilase Time

Specimen Containers and Fixatives

3.2% Sodium Citrate Blue Top Tube (2nd Tube Method)

Specimen Required

NorthShore Lab Services: draw 5.0 mL blood (see CLIENT SPECIAL INSTRUCTIONS), centrifuge twice and submit two 1 mL aliquots of frozen plasma in plastic tubes.

Hospital setting: submit 5.0 mL blood – see CLIENT SPECIAL INSTRUCTIONS.

Client Special Instructions

The specimen must be double centrifuged for special coagulation testing (e.g. lupus, protein C,

S etc.). Centrifuge specimens immediately (must be spun within 2 hours of collection). Carefully

remove plasma from cells avoiding platelets or red cells. Dispense into a plastic tube and centrifuge

plasma for 10 minutes. Remove the top portion of the plasma leaving approximately 250μl in the

bottom to discard. The double – centrifuged plasma should be aliquoted (1ml each) into clearly

labeled plastic tubes. Plastic tubes should be labeled with the patient's name, date of drawing, and

specimen number. The specimen should never come in contact with glass. If plasma cannot be sent to Evanston Special Coag lab within 4 hours of collection, freeze specimen and send it on dry ice.

Day(s) and Time(s) Performed


Monday – Friday (7AM – 3PM), 24 hours

Reference Values

13.8-26.7 seconds

This test is used to evaluate disturbances in fibrin formation and is an excellent substitute for thrombin time in the presence of heparin. Fibrin split products prolong the Reptilase time, but less than the thrombin time. A prolonged thrombin time and a normal Reptilase time indicates the presence of heparin. A prolonged thrombin time and strongly prolonged Reptilase time suggests dysfibrinogenemia or afibrinogenia.

Method Name

Clotting Assay

CPT Code Information