A simple method for assessing quinine pre-treatment in acute malaria

Area of Science:

• Pharmacology
• Infectious Diseases
• Clinical Diagnostics

Background:

• Quinine loading doses in severe malaria can be dangerous if therapeutic levels are already present due to prior treatment.
• Assessing prior quinine treatment reliability is crucial for patient safety.

Purpose of the Study:

• To evaluate the reliability of patient history regarding previous quinine treatment in acute falciparum malaria.
• To assess the efficacy of a rapid dipstick method for estimating plasma quinine concentrations.

Main Methods:

• A prospective study involving 379 adult patients with acute falciparum malaria in Thailand.
• Plasma quinine concentrations were measured using high-performance liquid chromatography (HPLC) and compared with patient history.
• A rapid semi-quantitative dipstick test using a monoclonal antibody was developed and validated against HPLC measurements.

Main Results:

• Patient history of quinine pretreatment was found to be unreliable, with low sensitivity (59%) and positive predictive value (53%).
• The rapid dipstick test demonstrated high sensitivity and specificity, with a strong correlation (0.85) to HPLC measurements.
• The dipstick test had a 100% negative predictive value for plasma quinine concentrations > 1 microgram/mL.

Conclusions:

• In Thailand, patient and relative history of quinine treatment is unreliable for acute falciparum malaria.
• The developed quinine dipstick test offers a simple, rapid, and reliable method for assessing quinine pre-treatment in malaria patients.
• This diagnostic tool can improve treatment safety by preventing dangerous quinine loading doses when therapeutic levels are already achieved.