Sensitive ELISA dipstick test for the detection of chloroquine in urine under field conditions

OBJECTIVE: To evaluate a new enzyme-linked immunosorbent assay (ELISA) dipstick test for detecting chloroquine (CQ) in urine in a malaria-endemic region of north-western Namibia. METHOD: Urine samples from 92 patients attending the outpatient department of Kamhaku Hospital with suspected malaria infection were tested for CQ with both the Dill-Glazko test and the ELISA dipstick test. Results were compared to the history of CQ intake as documented in the patients' health passes. RESULTS: The dipstick test proved an easy-to-handle and very sensitive tool for the detection of CQ with a lower limit of detection at 120 nmol/l. It showed high agreement with the history of CQ intake within the last 6 months. The specificity in a negative control group was 100%. The Dill-Glazko test was far less sensitive and specific with a lower detection limit of 150 micromol/l. CONCLUSION: The dipstick test can be used in pharmacological studies to evaluate the use of CQ, and as an inclusion criterion for in vivo and in vitro sensitivity tests, whereas the Dill-Glazko test is appropriate to test compliance during and a few days after CQ intake.