Volume 35, Issue 3 (May 1990)
Km(3) Identification by Enzyme-Linked Immunosorbent Assay (ELISA) as an Internal Control for Km(1) Activity Determined by Inhibition in Dried Bloodstains
A stability study comparing the identification of kappa marker Km(1), using the classical inhibition of agglutination, and the identification of Km(3), using an automated enzyme-linked immunosorbent assay (ELISA) technique, was done.
Preliminary tests were performed to establish the specificity and sensitivity of the methods. Based on the results, the quantities of stain required to detect each marker were determined.
Blood samples from 24 staff donors of known phenotype were aged at room temperature and at 37°C in the dried stain and liquid forms. In addition, 192 stains from cases 1 to 7 months old and 76 staff-donor stains from 1½ to 10 years old were tested in dried stain form.
The known sensitivity of the ELISA technique was exploited by deliberately testing a decreased quantity of antigen. As control stains were aged beyond the detectable limits of sensitivity, results consistently showed an almost simultaneous success or failure to detect Km(1) and Km(3). This indicates that the interpretive criteria established for ELISA are sufficiently demanding to eliminate the danger of reporting false Km(−1) results but true Km(3) results.