Negative: less than 5% red blood cell breakdown (hemolysis)
Positive: more than 10% hemolysis
The examples above are common measurements for results of these tests. Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples.Talk to your doctor about the meaning of your specific test results.
What abnormal results mean
Paroxysmal nocturnal hemoglobinuria (PNH)
Autoimmune hemolytic anemias and leukemia may give false positive result
What the risks are
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:
Fainting or feeling light-headed
Hematoma (blood accumulating under the skin)
Infection (a slight risk any time the skin is broken)
A negative test does not rule out PNH. False-negative results may occur if the fluid part of blood (serum) lacks complement.
Brodsky RA. Paroxysmal nocturnal hemoglobinuria. In: Hoffman R, Benz EJ, Shattil SS, et al, eds. Hematology: Basic Principles and Practice. 5th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2008:chap 30.
Todd Gersten, MD, Hematology/Oncology, Palm Beach Cancer Institute, West Palm Beach, FL. Review provided by VeriMed Healthcare Network. Also reviewed by Linda J. Vorvick, MD, Medical Director and Director of Didactic Curriculum, MEDEX Northwest Division of Physician Assistant Studies, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington; David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.