Calcium dobesilate: A drug treatment for diabetic retinopathy can negatively interfere with the measurement of glycated albumin using the enzymatic method.

BACKGROUND: We reported that calcium dobesilate, a vasoprotective agent mainly used for diabetic retinopathy (DR), negatively interferes with glycated albumin (GA) assays involving enzymatic methods.

METHODS: A calcium dobesilate standard was added to 3serum pools in vitro to prepare concentration-response series according to Clinical and Laboratory Standards Institute EP7-A2 guidelines. Percentage deviation between each drug concentration and the drug-free sample was calculated for 6 commercially available GA assays. The acceptable limit of deviation for GA was ±5.61%. For in vivo analyses, changes in serum concentrations of GA and calcium dobesilate were monitored in eight healthy participants before and after oral calcium dobesilate administration.

RESULTS: At 16 μg/ml calcium dobesilate, within the therapeutic range, the percentage deviations for Asahi Kasei, Maccura, Leadman, Homa, and Medicalsystem assays were -8.7% to -49.7%, -2.0% to -47.7%, and -10.1% to -35.7% for low-, medium- and high-GA level interference pools, respectively, exhibiting dose-dependent negative interference. In vivo, calcium dobesilate ingestion was associated with statistically significant, falsely decreased measurements in 5 GA assays, 2 h after daily 500 mg administration.

CONCLUSIONS: Calcium dobesilate ingestion was associated with erroneously low measurements in 5 GA assays. The degree of interference varied greatly among the assays examined.