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Medical Author:

Mary Nettleman, MD, MS, MACP

Mary Nettleman, MD, MS, MACP

Mary D. Nettleman, MD, MS, MACP is the Chair of the Department of Medicine at Michigan State University. She is a graduate of Vanderbilt Medical School, and completed her residency in Internal Medicine and a fellowship in Infectious Diseases at Indiana University.

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Medical Editor:

Charles Patrick Davis, MD, PhD

Charles Patrick Davis, MD, PhD

Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

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Malaria Diagnosis

Many diseases cause fever in the tropical and subtropical world, including malaria, tuberculosis, yellow fever, dengue fever, typhoid, and cholera. Each of these is managed differently. Thus it is very important to make a specific diagnosis.

Malaria is diagnosed by seeing the parasite under the microscope. Blood taken from the patient is smeared on a slide for examination. Special stains are used to help highlight the parasite. Sometimes, it is possible to identify the species of Plasmodium by the shape of the parasite, especially if gametocytes are seen. Whenever possible, smears should be reviewed by someone with expertise in the diagnosis of malaria. If the smears are negative, they can be repeated every 12 hours. Smears that are repeatedly negative suggest another diagnosis.

Two types of other tests are available for diagnosis of malaria. Rapid tests can detect proteins called antigens that are present in Plasmodium. These tests take less than 30 minutes to perform. However, the Food and Drug Administration and the Centers for Disease Control and Prevention recommend that these new tests be used in conjunction with microscopy. A second type of test that is newly available is the polymerase chain reaction (PCR), which detects malaria DNA. Because this test is not widely available, it is important not to delay treatment while waiting for results.