Rationale:

• Delays in accurate diagnosis of malaria increase morbidity and mortality.
• Although most clinical microbiologists may be able to perform blood smears properly, few will be experts in examining them for malaria parasites.

Evidence:

• From 1963 to 2001, there were 123 fatalities reported among U.S. travelers with malaria. For those for whom relevant information was available, 68% did not obtain a diagnosis of malaria on the same day as the initial medical visit, and 18% were diagnosed only at autopsy (45).
• False-negative blood smears and missed diagnoses are not uncommon (80).
• In one community-based study, microscopic diagnosis provided incorrect species identification in 64% of cases (81).
• Patients who present to clinics without expertise in tropical medicine are likely to receive suboptimal treatment (81).

Comments:

• Before an acute need arises, identify the clinical microbiologist at your institution responsible for the emergency preparation and reading of blood smears. In most cases, the clinical microbiologist responsible for malaria diagnosis will not be working evening or night shifts and will have to be called in from home. Some consultants in infectious diseases may also be willing to make themselves available for emergency reading of blood smears.
• Diagnostic procedures and examples of microscopic images are available from the CDC's Laboratory Identification of Parasites of Public Health Concern under specimen processing, microscopic exam, and bench aids for blood specimens.