Sugar-water hemolysis test

Toggle: English / Spanish


The sugar-water hemolysis test is a blood test to detect fragile red blood cells. It does this by testing how well they withstand swelling in a low-salt solution.

Alternative Names

Sucrose hemolysis test; Hemolytic anemia sugar water hemolysis test; Paroxysmal nocturnal hemoglobinuria sugar water hemolysis test; PNH sugar water hemolysis test

How the Test is Performed

A blood sample is needed.

How to Prepare for the Test

There is no special preparation needed for this test.

How the Test will Feel

When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or a slight bruise. This soon goes away.

Why the Test is Performed

Your health care provider may recommend this test if you have signs or symptoms of

(PNH) or of unknown cause. Hemolytic anemia is a condition in which red blood cells die before they should. PNH red blood cells are very likely to be harmed by the body's "complement system." The complement system are proteins that move through the bloodstream. These proteins work with the immune system.

Normal Results

A normal test result is called a negative result. A normal result shows that less than 5% of red blood cells break down when tested. This breakdown is called hemolysis.

A negative test does not rule out PNH. False-negative results may occur if the fluid part of blood (serum) lacks complement.

Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your provider about the meaning of your specific test results.

What Abnormal Results Mean

A positive test result means the results are abnormal. In a positive test, more than 10% of red blood cells break down. It could indicate the person has PNH.

Certain conditions can make the test results appear positive (called "false positive"). These conditions are autoimmune hemolytic anemias and leukemia.


There is very little risk involved with having your blood taken. Veins and arteries vary in size from one person 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:

  • Excessive bleeding
  • Fainting or feeling lightheaded
  • Hematoma (blood buildup under the skin)
  • Infection (a slight risk any time the skin is broken)


Brodsky RA. Paroxysmal nocturnal hemoglobinuria. In: Hoffman R, Benz EJ Jr, Silberstein LE, et al, eds. Hematology: Basic Principles and Practice. 6th ed. Philadelphia, PA: Elsevier Saunders; 2013:chap 29.

Gallagher PG. Hemolytic anemias. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 25th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 161.

Version Info

  • Last reviewed on 2/11/2016
  • Todd Gersten, MD, Hematology/Oncology, Florida Cancer Specialists & Research Institute, Wellington, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission ( URAC's accreditation program is an independent audit to verify that A.D.A.M. follows rigorous standards of quality and accountability. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial policy, editorial process and privacy policy. A.D.A.M. is also a founding member of Hi-Ethics and subscribes to the principles of the Health on the Net Foundation (

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- 2013 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.