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Alternative Names
Anti-P antibodyDefinition Return to top
The Donath-Landsteiner test is a blood test to detect harmful antibodies related to a rare disorder called paroxysmal cold hemoglobinuria. The antibodies form and destroy red blood cells when the body is exposed to cold temperatures.
How the Test is Performed Return to top
Blood is drawn from a vein, usually from the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic. An elastic band or blood pressure cuff is placed around the upper arm to apply pressure and restrict blood flow through the vein. This causes the vein to swell with blood.
A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. During the procedure, the band is removed to restore normal blood flow. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.
In infants or young children, the area is cleansed with antiseptic and punctured with a sharp needle or a lancet. The blood may be collected in a small glass tube (pipette), on a slide, onto a test strip, or into a small container. Cotton or a bandage may be applied to the puncture site if there is any continued bleeding.
How to Prepare for the Test Return to top
No special preparation is needed.
How the Test Will Feel Return to top
When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.
Why the Test is Performed Return to top
This test is done to confirm a diagnosis of paroxysmal cold hemoglobinuria.
Normal Results Return to top
No presence of antibodies is normal.
What Abnormal Results Mean Return to top
Abnormal results mean Donath-Landsteiner antibodies are present. This is a sign of paroxysmal cold hemoglobinuria (PCH).
Risks Return to top
There is very little risk involved with having your blood taken. Veins and arteries vary in size from one patient to another and from one side of the body to the other. Taking blood from some people may be more difficult than from others.
Other risks associated with having blood drawn are slight but may include:
References Return to top
Schwartz RS. Autoimmune and intravascular hemolytic anemias. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 164.
Update Date: 2/21/2009 Updated by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
