Friday, June 15, 2007

Introduction to ELISA Procedure

The goal of our lab work this week has been to determine which progesterone assays will work for bovine serum and milk. The two assays we have tried thus far were both designed for human serum. We first produced standard curves with progesterone samples provided in the kit or via serial dilution to determine if the assays were functioning properly. Bovine serum and milk samples were collected from cows enrolled in the G6G Ovsynch program at Nobis Dairy on days where natural progesterone levels were at their lowest concentration. These samples will provide our negative controls. The second day we repeated the standard dilutions and compared them to bovine serum and milk samples which had been spiked with equivalent concentrations of progesterone. This allowed us to look for components in milk or serum samples that may interfere with the reagents of the human progesterone assays. The assays were also run with undiluted, unaltered serum and defatted milk samples from the negative control samples. The assays which will be used for a marketable product need to perform well with unaltered samples of milk. Any extra processing required in an assay drives up production costs and will not allow us to offer a product at an affordable price to producers.

Therefore, I have begun my crash course in ELISAs. Running ELISA's consists of accurately pippetting minute quantities of reagents into small microtiter wells. This sounds fairly simple, especially when well-quipped with sophisticated equipment. I have learned that the degree of accuracy increases with the number of ELISAs the lab tech has run. This is very evident when I try to produce equivalent results when processing duplicate rows of samples compared to the lab techs that make everything look very easy when they dispense their billionth sample.