international normalised ratio (INR)


INR for monitoring warfarin

Also known as


Additional information

Fill exactly to the line indicated on the bottle. Sample must arrive within 2 hours of collection. Capillary samples are unsuitable for coagulation tests. If peerformed with a coagulation screen, no extra sample is required.Screen comprises PT, APTT, thrombin time and fibrinogen. If the patient is on warfarin or heparin, please indicate this on the request form.

Sending address

Department of Haematology Camelia Botnar Laboratories Great Ormond Street Hospital Great Ormond Street WC1N 3JH

Laboratory service


Sample requirements

1.4ml venous blood, citrate

Turnaround time

3 hours


Upon request

Call in advance?

Not required


The Haematology Department provides a wide range of specialist tests with a special interest in the diagnosis and monitoring of coagulation disorders.

© 2011 Great Ormond Street Hospital for Children NHS Trust