Comparison of methodologies for microscopic malaria diagnosis

Area of Science:

• Medical Parasitology
• Infectious Disease Diagnostics
• Public Health Entomology

Background:

• Malaria diagnosis quality is crucial for Colombia's pre-elimination strategy.
• Improving access and quality of malaria diagnosis is a key objective.

Purpose of the Study:

• To compare the Pan American Health Organization/World Health Organization (PAHO/WHO) recommended methodology with Colombia's current malaria diagnostic method.
• Evaluate diagnostic accuracy and reliability under various conditions.

Main Methods:

• Collected 88 blood samples for malaria diagnosis slide preparation.
• Performed duplicate microscopic readings and variance calculations for staining and methodology comparisons.
• Assessed parasite density at 500, 1,000, 5,000, and 10,000 parasites/μl.

Main Results:

• Achieved a high inter-rater agreement with a Cohen kappa index of 0.923.
• No statistically significant effect of stain, methodology, or their interaction on diagnostic results was found.
• The modified Romanowsky stain and combined thick smear method demonstrated robust performance.

Conclusions:

• The preparation of two thick smears stained with modified Romanowsky is a suitable malaria diagnostic methodology for Colombia.
• This method offers technical advantages, including ease of storage, low cost, and simple use.
• The findings support the integration of this methodology into national malaria control programs.