What is the accepted method for Natural Rubber Latex protein testing?

Currently, there are 2 different test methods that are considered industry standards to test the proteins in natural rubber latex: (1) Modified Lowry and (2) ELISA. The test that has been around the longest is the Modified Lowry. This method, referred to as ASTM D 5712-05, was approved in April 1995 and updated in 2005. The test measures the total water extractable protein on a latex product including, but not limited to, any milk protein (used by some manufacturers), enzymes, natural rubber latex proteins and any other types of protein present.

The second most frequently used test is the ELISA test. The ELISA test is referred to as the ASTM D 6499-07 Standard Test Method for the Immunological Measurement of Antigenic Protein in Natural Rubber and its Products ELISA Inhibition Assay uses an Inhibition ELISA to quantify antigenic latex protein in product extracts. In the ELISA, soluble antigens in the extract compete for binding to specific anti-latex antibodies and block antibody binding to latex antigen immobilized on the surface of the assay plate. Results are usually expressed in micrograms of antigenic protein per gram (ug/g) or square decimeter (ug/dm2) (a measurement of surface area).