Dilution as a source of error: implications for preparation and calibration of laboratory standards and for quality control of radioimmunoassays.

Although dilution of materials is generally accepted to involve some error, workers often assume that this error may be discounted. However, comparing solutions of two identical materials diluted in the same way shows that dilution errors can cause a considerable departure from the expected identity. I describe this effect and its dependence on the errors at various stages of the dilution process.