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Updated: Aug 24, 2026
Dried Blood Spots - Preparing and Processing for Use in Immunoassays and in Molecular Techniques
Published on: March 13, 2015
Modification of CMV DNA detection from dried blood spots for diagnosing congenital CMV infection
Sandro Binda1, Simona Caroppo, Patrizia Didò
1Istituto di Virologia, Università di Milano, Via Pascal 38, 20133 Milan, Italy.
Background:
Detection of viral DNA in dried blood spots using the Guthrie card (DBS test) is a reliable and practical method of diagnosing congenital cytomegalovirus (CMV) infection. The test lends itself to epidemiological studies to establish the prevalence of the infection, but also to neonatal screening for secondary prevention of sequelae. These applications would be facilitated if it were possible to use smaller samples and do the test on pools of individual cases.
Objective:
To ascertain whether doing the test on smaller, pooled samples still accurately identifies neonates with congenital CMV infection.
Study Design:
We tested DBS from: (A) 39 laboratory reference cases; (B) 156 neonates suspected of having congenital CMV infection; (C) 119 children examined for the retrospective diagnosis of congenital CMV; (D) mock specimens prepared with known amounts of viral DNA.
Results:
The test using only one third of the usual amount of dried blood was 100% sensitive and specific compared to the standard DBS test (A) and to viral isolation (A and B). Pools of three single cases gave the same results as viral isolation (B) and the small-sample test (B and C). All the versions of the test gave a detection limit of 400 copies/ml.
Conclusions:
The modified procedure can accurately diagnose congenital CMV infection. It achieves savings in both the patient material and the costs of testing.
