Prothrombin time

Test information: Prothrombin is a protein made by the liver. Prothrombin helps blood to clot. The "prothrombin time" (PT) is one way of measuring how long it takes blood to form a clot, and it is measured in seconds. The PT measures the activity of the Extrinsic and common factors of the Coagulation pathway. It is used alongside the Activated Partial Thromboplastin Time (APTT) as a general screening procedure for clotting abnormalities, liver function assessment and for monitoring patients receiving Warfarin anticoagulant therapy.

Specimen Type(s)

• Blood;

Other Acceptable Specimen Type(s)

N/A

Specimen Container - Adult

• Light Blue Top BD;

Specimen Container - Paediatric

• N/A;

Analytes

• N/A;

Part of a test profile?

Thrombophilia screen

Volume (min) of sample to be sent to laboratory

4ml

Patient Preparation, Sample Handling and Transport

Coagulation samples are volume critical, if a patient is difficult to bleed paediatric tubes (1.3ml) are available on request. Some patients with a grossly raised Haematocrit (HCT) >0.57 may give erroneous coagulation test results - individual patient adjusted volume coagulation tubes are available on request from the laboratory. Please make a note of any anticoagulants and/or bleeding/bruising symptoms.

Maximum add on time

24 hours

Units and Reference Ranges / Interpretation

Interpretative comments

UKAS number

8869

UKAS accredited test?

Yes

Comments

N/A

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