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Lupus anticoagulant screen


Lupus anticoagulant screen
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Reference Range:

Contact laboratory for interpretation of result

Turnaround Time:

5 days


Please see under immunology section for anticardiolipin


Lupus anticoagulant is associated with arterial and venous thromboembilism and neurological disease. It has been implicated in recurrent spontaneous abortion. These inhibitors usually prolong the the activated partial thromboplastin time (APTT)


For Lupus screen, 9 volumes of blood added to 1 volume of sodium citrate solution. This ratio of anticoagulant to blood is critical as osmotic effects and changes in free calcium ion concentrations affect the coagulation results. Obtaining blood from an in-dwelling line or catheter is a potential source of error due to likely heaprin contamination, therefore sampling from those is unacceptable.

Vessels and Containers:

Four 4.5 ml Citrate Samples

Sample Requirements:

Careful collection using a 19G needle with minimal stasis to avoid platelet activation, if possible do not use a tourniquet. Samples should be processed within 1 hour of sampling by double centrifugation. The sample is then frozen if not being analysed immediately


Sample collection and handling can markedly affect the results. Inadequate removal of platelets will adversly affect results. There are no reliable methods for measuring Lupus anticoagulant when the patient is on anticoagulant therapy

How result is reported:

Abnormal results will be refered to the Haematology Consultant responsible for Coagulation

Important Information:

Underfilled samples will invalidate results
Haemolysis will invalidate results
All medication must be written on the request form


Lupus LA

Transportation and Handling:

Samples should be transported to the laboratory within 1 hour of sampling. If separated and frozen samples should be transported on dry ice

Special Precautions:

When performing separation of plasma from primary tubes avoid contamination with plateletes