A rapid tube ELISA for human IgG in body fluids using Staphylococcus aureus

An ELISA was designed for measurement of human IgG in urine and CSF using protein A containing Staphylococcus aureus as sorbent. This assay was performed in test tubes. An OD difference of approximately 1.0 was developed between non-specific binding and 10 micrograms/ml IgG solution. The method has a sensitivity of 70 ng IgG/ml. The test is simple and rapid and does not require concentration of samples. Once prepared S. aureus reagent is stable for at least one year. The merits of this method in comparison to radial immunodiffusion (RID) are discussed.