High frequency of parvovirus B19 in patients tested for rheumatoid factor

Abstract
Remaining serum from 503 consecutive samples submitted for a rheumatoid factor test was collected prospectively between December 1992 and February 1993. Samples from blood donors (348) and from inpatients requiring blood transfusions (333), also collected during these months, served as controls. Clinical data were obtained retrospectively from records. B19 DNA was identified using a method for screening large numbers of samples.2