anti-Xa assay (low molecular heparin)


anti-Xa assay for monitoring low molecular heparin

Also known as

anti Xa assay

Additional information

Fill exactly to the line indicated on the bottle. Sample must arrive within I hour of collection. 0.5ml neonatal coagulation bottles are unsuitable for this test. If the sample is not taken by a peripheral route, it is essential to avoid heparin contamination. Capillary samples are unsuitable for coagulation tests. Samples must be taken 4-6 hours post last dose of low molecular weight heparin. External requests must use the Great Ormond Street anti-Xa (low molecular weight heparin) 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 (0.5ml neonatal coagulation bottles are unsuitable for this test)

Turnaround time

12 hours


Upon request

Call in advance?

Please contact the laboratory when sending urgent samples.


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