Ham test

Ham test is a medical diagnostic test used to identify Paroxysmal Nocturnal Hemoglobinuria (PNH), a rare genetic disorder that causes the destruction of red blood cells. The test is named after Dr. Thomas Hale Ham, who first described the procedure in 1937.

Overview

The Ham test, also known as the acidified serum test, is a laboratory method used to diagnose PNH. The test is based on the principle that red blood cells from individuals with PNH are more susceptible to complement-mediated lysis when exposed to mildly acidified serum.

Procedure

In the Ham test, a patient's red blood cells are mixed with acidified serum at 37 degrees Celsius. If the red blood cells are lysed (broken down), the test is considered positive, indicating the presence of PNH.

Significance

The Ham test was the first diagnostic test for PNH and was widely used until the 1990s. However, it has largely been replaced by more sensitive and specific tests, such as flow cytometry. Despite this, the Ham test remains a significant part of the history of PNH research and diagnosis.

Limitations

While the Ham test was a breakthrough in PNH diagnosis, it has several limitations. The test can produce false-positive results in other hemolytic disorders, and it is less sensitive than newer diagnostic methods. Furthermore, the test requires fresh serum, which can be difficult to obtain and handle.

See Also

• Paroxysmal Nocturnal Hemoglobinuria
• Flow Cytometry
• Hemolytic Disorders