Mycobacterium avium Complex (MAC)

November 2004     View PDF     En español

Diagnosis

MAC is diagnosed by culture from blood, tissue or bone marrow. If MAC bacteria are found in stool and sputum samples, this could mean the infection has spread. Doctors may have to use special methods to get cells or tissue for MAC diagnosis. These include taking bone marrow from the hip using a needle, or inserting a flexible tube into the stomach or bowels (endoscopy) or the lungs (bronchoscopy).

Some doctors choose to treat MAC infection while waiting for the test results, which can take several weeks. New tests are being developed to give a faster diagnosis. These include PCR and bDNA tests for MAC (the same methods used for HIV viral load tests). Severe anemia and liver problems can occur in MAC, so doctors may take blood samples to look for a low red blood cell count or raised alkaline phosphatase levels.