BACKGROUND: Recipients of umbilical cord blood (UCB) transplants are susceptible to opportunistic infections, including cytomegalovirus (CMV). To prevent CMV transmission from UCB donors, most laboratories perform serology on corresponding maternal samples and quarantine units when the mother has immunoglobulin M (IgM) anti-CMV.

STUDY DESIGN AND METHODS: UCB units and associated samples (UCB plasma and red cell pellet; maternal whole blood and serum) from two cord blood banks were tested with two validated CMV polymerase chain reaction assays (UL54 and UL93 targets). Results were compared with maternal CMV serology (IgG and IgM).

RESULTS: Only 4 of 48 (8.3%) quarantined CMV IgM–positive units were also CMV nucleic acid testing (NAT)-positive (651-68,600 copies/mL). In contrast, 1 of 200 “CMV-safe” UCB units (CMV IgM–equivocal or –negative) had CMV DNA (0.5%). The corresponding maternal samples were CMV NAT–negative. Positive maternal IgM serology demonstrates only modest sensitivity (80%) and specificity (82%) and poor positive predictive value (8%), when correlated with the presence of CMV DNA in UCB units.

CONCLUSION: CMV NAT may be a useful adjunct to serologic screening, potentially reducing wastage of IgM-positive and NAT-negative units while also detecting potentially infectious units that would pass serologic screening. A prospective clinical trial to further evaluate the role of CMV NAT in UCB transplantation appears warranted.