A PUMCH Laboratory team, led by Qiu Ling, Guo Xiuzhi and working together with pharmacists, nephrologists and Chinese companies on in-vitro diagnostic reagents, successfully developed a Cr assay kit that resists Calcium Dobesilate interference. It completely solved the problem that the take-in of Calcium Dobesilate causes false decrease of Cr, leading to underestimation of kidney damage and delay in treatment. As the first of its kind in China, its anti-interference capability is 12.5 times stronger than imported ones, for which registration has been obtained recently. The project won the third prize of 2018 PUMCH Sci-tech Transformation Award.
Cr is the most commonly used clinical indicator of kidney functions, and more than 70% Chinese labs use sarcosine oxidase in tests. Calcium Dobesilate is a drug for microvascular protection, often used on the treatment and prevention of diabetic retinopathy (DR) and glomerulosclerosis, and shows a tendency of being increasingly applied.
In 2011, the hospital found big Cr fluctuations in short term in a diabetic nephropathy patient, while urea, another indicator of kidney function, remained high. Through clinical communication and searching into the patient’s medical history and related literature, doctors found that the Calcium Dobesilate the patient took in produced an obvious negative interference in Cr test. Similar cases followed, casting a remarkable impact on diagnosis and treatment.
Supported by the Capital Medical Development Scientific Research Fund, the team, based on an early-stage, small-scale experiment, carried out systematic research, and for the first time proved the commonness and seriousness of the drug’s interference on Cr test through sarcosine oxidase. Assessment of eight test platforms popular on market showed that the drug, even at lowest concentration, is obviously interfering all testing systems; at highest concentration, it can interfere a reagent to -60%. Ten researchers from the team tested the drug on themselves, and assessed the quantitative relationship; and, through the correctness verification project of the Clinical Laboratory Center of the Ministry of Health, issued twice testing samples containing Calcium Dobesilate to more than 300 labs, which further proved the commonness and seriousness of such interference across China.
The team, working together with Chinese companies on in-vitro diagnostic reagents and based on verification experiments of four hypotheses, was the world first to find out the interference mechanism. It also proved that the drug also interferes negatively uric acid and Triglyceride, which are based on the same testing mechanisms. It was also the first to report serious negative interference of the drug in the testing of FFA and GA.
The team looked for marketing the findings. It worked together with two Chinese companies to improve the testing kit. The anti-interference reagent from one of them has been granted state patent in August 2018, and was registered as an in-vitro diagnostic reagent in December of the same year. As the first of its kind in China, its anti-interference capability is 12.5 times stronger than imported ones. The team hopes, through technology transfer, to push the more than 60 Chinese manufacturers of similar reagents to improve their product.
The team also focused on giving clinical warnings, and through academic meetings, lectures and WeChat, continuously reminded doctors, examiners, pharmacists and patients of the interference. According to Professor Qiu Ling, deputy director of PUMCH Laboratory, if a patient is given Calcium Dobesilate, it is suggested that Cr, lipids and other indicators are tested 3-5 days after stopping the drug, when the interference is at lowest.