Detecting diclofenac in livestock carcasses in India with an ELISA: A tool to prevent widespread vulture poisoning

Diclofenac, a non-steroidal anti-inflammatory drug (NSAID), has caused catastrophic vulture declines across the Indian sub-continent. Here, an indirect ELISA is used to detect and quantify diclofenac in 1251 liver samples from livestock carcasses collected across India between August 2007 and June 2008, one to two years after a ban on diclofenac manufacture and distribution for veterinary use was implemented. The ELISAs applicability was authenticated with independent data obtained using LC–ESI/MS. Of 1251 samples, 1150 (91.9%) were negative for diclofenac using both methods, and 60 (4.8%) were positive at 10–4348 and 10–4441 μg kg−1 when analysed by ELISA and LC–ESI/MS, respectively. The residue level relationship in the 60 positive samples was highly significant (p < 0.001, r2 = 0.644). Data suggest that this immunological assay could be used not only for cost effective sample screening, but also for residue level semi-quantification.

► An ELISA is validated for use in diclofenac monitoring.
► We compare ELISA and LC–ESI/MS data for 1251 samples.
► Results indicate the ELISA can be reliably used for screening and semi-quantification.
► In 2007–2008, in India, around 1 in 20 ungulate carcasses contained detectable diclofenac.