Laboratory Test Directory

Thrombin Time: (089-0436)

Clinical Indication:

Useful in the diagnosis and/or detection of hypofibrinogenemia, dysfibrinogenemia, fibrin degradation products, or dysproteinemia.

Test Mnemonic:

 THROMBIN

Methodology:

 Electromagnetic Viscosity Detection

Performed:

 Samples are accepted 24 hours per day at Sample Management, 5.136 McCullough Bldg.

Turnaround Time:

  STAT: 1 hour; ROUTINE: 4 hours

Specimen Requirements:

Collect: Blue-topped (3.2% sodium-citrate) tube. Routine venipuncture; discard 1st mL of blood by collecting a discard tube prior to collecting the blue-topped (3.2% sodium-citrate) tube.  For collections with butterfly blood collection sets, a discard tube should also be collected prior to collection of the blue top to ensure sufficient sample volume. Drawing a discard tube will displace the air from the blood collection set tubing to ensure proper blood draw volume.

Specimen Preparation:  Acceptable up to 4 hours after collection, at ROOM TEMPERATURE.

Storage/Transport: NOTE:  If delivery time is to be greater than 4 hours from time of draw, centrifuge the sample for 10 minutes at 2500g.   Separate the plasma from the cells and store at room temperature. For patients on heparin therapy, the blood must be centrifuged and the plasma separated from cells within 1 hour of collection.

 Stability: Whole blood 4 hours at room temperature. Plasma storage 8 hours at 20+/- 5°C.   Patients on heparin therapy, plasma is stable for 2 hours at 20+/- 5°C. 

Causes for Rejection: QNS, clotted, severely hemolyzed specimen, specimen greater than 4 hours old or 2 hours old for patients on heparin therapy, wrong tube (3.8% sodium citrate), high hematocrit (> 55%), sample identification error, sample processed/transported, and/or stored improperly.

Clinical Information:

Interfering Substances: Heparin

Reference Range:

14.9 - 18.5  seconds

CPT 4 Code:

85670

Reviewed: 3/20/13

 W.Russo, MT(ASCP)

When ordering tests for which Medicare or Medicaid reimbursement will be sought, physicians should only order tests that are medically necessary for the diagnosis or treatment of the patient.  Components of the organ or disease panels may be ordered individually.  The diagnostic information must substantiate all tests ordered and must be in the form of an ICD-9 code or its verbal equivalent.