Factors influencing detection of quantitative cytomegalovirus antigenemia.

Of 20 blood specimens testing positive for cytomegalovirus antigen after immediate processing, 19 (95%) remained positive when kept at room temperature for 24 h before processing. Quantitative antigenemia decreased by an average of 44% after storage. Compared with acetone fixation, formaldehyde fixation showed improved readability, fewer artifacts, and a higher degree of sensitivity.