Reptilase Clotting Time

Message

*Take to procssing ASAP. Must be spun down and frozen within an hour of collection.

Test Code

37700

Alias/See Also

LAB1136

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

Platelet poor-plasma: Centrifuge light blue-top tube for 15 minutes at approximately 1500g within 60 minutes 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. Plasma must be free of platelets (<10,000/uL). Freeze immediately and ship on dry ice.

Transport Container

Transport tube

Transport Temperature

Frozen

Specimen Stability

Room temperature: 8 hours
Refrigerated: 24 hours
Frozen: 30 days

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Received room temperature • Received refrigerated

Methodology
Clot Based Assay

Setup Schedule

Mon

Report Available

Next day

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-Chantilly VA

14225 Newbrook Drive

Chantilly, VA 20151-2228

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.