Closure Time

Test Code

CLOSURE

Preferred Specimen

Blood

Minimum Volume

1.00 ML

Instructions

***Sample must be collected at IRMC Main Campus Laboratory***

Four (4) Blue Top (3.2% Sodium Citrate) tubes at room temperature

Maintain specimen as whole blood at room temperature and transport to the laboratory immediately.

Must be received in the laboratory within four (4) hours of collection. Do not chill or transport via pneumatic tube - platelets are activated at low temperature and with vigorous aggitation.

Transport Container

Lavender, Blue

Methodology
In vitro blood flow analysis. The process of platelet aggregation builds a platelet thrombus at the aperture thereby diminishing and finally restricting blood flow. The time from the start of the test until the platelet plug occludes the aperture is reported as the closure time in seconds.

Clinical Significance

It is clinically important to assess platelet function as a potential cause of bleeding diathesis. Closure times may be useful in the following situtions:

Patients with clinical suspicion of von Willebrand's disease

Patients with a family history of bleeding or heavy bruising

Monitoring of ASA/NSAID use

Therapeutic response to DDAVP

Uremia

Screening for inherited platelet disorders

Performing Laboratory
Indiana Regional Medical Center

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.