Name: Thrombin Time
Test Name: Thrombin Time
Health Link Test Code: HCCTT
LIS Test Code: CTT
CPT Code(s): 85670
Included In: May be included in a Lupus Anticoagulant Work-Up.
Methodology: Photo-Optical Clot Detection
The thrombin time measures the rate of fibrinogen to fibrin conversion in plasma in the presence of limited quantities of thrombin.
Prolongation of the thrombin time occurs when: the fibrinogen content is very low (less than 100 mg/dL), fibrin degradation products (FDP) are very high, heparin is present, or the fibrinogen is abnormal (i.e., dysfibrinogenemia).
Days Performed: Mon-Fri, dayshift - day varies. Specimens are accepted at any time. Testing required during off hours must be approved by a Coagulation physician. Call 263-5005 before collection.
In-Lab Turnaround Time: 4 - 10 days.
Stat In-Lab Turnaround Time: 1 day.
Collection Container: Light blue top (3.2% NaCitrate)
Do NOT draw through a line containing heparin. The venipuncture MUST be atraumatic to avoid hemolysis and contamination with tissue factors and platelets. Tube must be allowed to fill completely.
Please indicate patient history and if patient is receiving anticoagulant (Coumadin/Heparin/Vitamin K antagonist), direct thrombin inhibitor or fibrinolytic agent therapy and duration.
Collection Volume: Full 3.5 mL tube
Pediatric Collection Volume: Pediatric tube filled to fill mark
4 hours on a spun tube
2 weeks at -20°C; 6 months at -70°C
Sample Analyzed: Plasma
Testing Volume: 1 mL
Pediatric Testing Volume: 1 mL
Centrifuge specimen to yield platelet poor plasma (platelet count should be less than 10 K/uL). Separate plasma and transfer to plastic tube or vial. Freeze plasma within 4 hours of collection at -20°C or below.
Transport whole blood specimen at room temperature to UWHC Hospital Laboratory within 4 hours of collection. See Specimen Processing for instructions if transport criteria are not met. Transport frozen plasma aliquot on dry ice to UWHC Hospital Laboratory.
Hemolyzed specimens, clotted specimens, partially filled tubes and whole blood specimens greater than 4 hours old when received by the laboratory are not acceptable.
0 days and up: 15.8 - 24.9 seconds
Interpretation Type: Reference Interval