Reptilase Clotting Time

Test Code

Quest Code

37700

CPT Codes
85635

Preferred Specimen

1 mL frozen plasma collected in a 3.2% Sodium Citrate (light blue-top) tube

Minimum Volume

0.5 mL

Instructions

Please submit a separate, frozen vial for each special coagulation assay ordered.

Draw blood in light blue-top tube containing 3.2% sodium citrate (light blue-top) tube, and mix gently by inverting 3-4 times. Centrifuge 15 minutes at 1500 x g within 1 hour of collection. Using a plastic pipette, remove plasma, taking care to avoid the WBC/platelet buffy layer and place into a plastic vial. Centrifuge a second time and transfer platelet-poor plasma into a new plastic vial(s). Freeze immediately and transport on dry ice.

Transport Container

Transport tube

Transport Temperature

Frozen

Specimen Stability

Room temperature: Unacceptable
Refrigerated: Unacceptable
Frozen -20°C: 30 days
Frozen -70°C: > 30 days

Methodology
Clot Based Assay

Setup Schedule

Set up: Mon; Report available: 1-8 days

Reference Range

14-20 seconds

Clinical Significance

In patients with prolonged clotting times, this test may help diagnose dysfibrinogenemia or exclude heparin contamination. In heparinized or hemophiliac patients, this test may be used in conjunction with or instead of thrombin time to help diagnose congenital and acquired disorders of fibrinogen [1].

Reptilase is a venom enzyme from Bothrops snakes and has thrombin-like activity. Reptilase time is often used in conjunction with thrombin time to detect anomalies of fibrinogen. These anomalies can be congenital (eg, dysfibrinogenemia, hypofibrinogenemia, afibrinogenemia) or acquired (eg, hypofibrinogenemia as a result from disseminated intravascular coagulation or liver disease). In patients with abnormal clotting times, thrombin time and reptilase time can help screen for dysfibrinogenemia [2]. Because reptilase time is insensitive to thrombin inhibitors (eg, heparin or hirudin), it can be used to determine heparin contamination in patients with prolonged clotting times [1]. A prolonged thrombin time and a normal reptilase time generally indicate heparin contamination.

Note that reptilase time may be slightly prolonged in healthy newborns [1].

The results of this test should be interpreted in the context of pertinent clinical and family history and physical examination findings.

References
1. Cunningham MT, et al. Arch Pathol Lab Med. 2002;126(4):499-505.
2. Karapetian H. Methods Mol Biol. 2013;992:273-277.

Performing Laboratory
Quest Diagnostics Nichols Institute
14225 Newbrook Dr
Chantilly, VA 20153

Last Updated: August 26, 2019

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.