title: Dried blood spot real-time polymerase chain reaction assays to screen newborns for congenital cytomegalovirus infection.
abstract: BACKGROUND
  Reliable methods to screen newborns for congenital cytomegalovirus (CMV) infection are needed for identification of infants at increased risk of hearing loss. Since dried blood spots (DBS) are routinely collected for metabolic screening from all newborns in the United States, there has been interest in using DBS polymerase chain reaction (PCR)-based methods for newborn CMV screening.
  
  
  OBJECTIVE
  To determine the diagnostic accuracy of DBS real-time PCR assays for newborn CMV screening.
  
  
  METHODS
  Between March 2007 and May 2008, infants born at 7 US medical centers had saliva specimens tested by rapid culture for early antigen fluorescent foci. Results of saliva rapid culture were compared with a single-primer (March 2007-December 2007) and a 2-primer DBS real-time PCR (January 2008-May 2008). Infants whose specimens screened positive on rapid culture or PCR had congenital infection confirmed by the reference standard method with rapid culture testing on saliva or urine.
  
  
  METHODS
  Sensitivity, specificity, and positive and negative likelihood ratios (LRs) of single-primer and 2-primer DBS real-time PCR assays for identifying infants with confirmed congenital CMV infection.
  
  
  RESULTS
  Congenital CMV infection was confirmed in 92 of 20,448 (0.45%; 95% confidence interval [CI], 0.36%-0.55%) infants. Ninety-one of 92 infants had positive results on saliva rapid culture. Of the 11,422 infants screened using the single-primer DBS PCR, 17 of 60 (28%) infants had positive results with this assay, whereas, among the 9026 infants screened using the 2-primer DBS PCR, 11 of 32 (34%) screened positive. The single-primer DBS PCR identified congenital CMV infection with a sensitivity of 28.3% (95% CI, 17.4%-41.4%), specificity of 99.9% (95% CI, 99.9%-100%), positive LR of 803.7 (95% CI, 278.7-2317.9), and negative LR of 0.7 (95% CI, 0.6-0.8). The positive and negative predictive values of the single-primer DBS PCR were 80.9% (95% CI, 58.1%-94.5%) and 99.6% (95% CI, 99.5%-99.7%), respectively. The 2-primer DBS PCR assay identified infants with congenital CMV infection with a sensitivity of 34.4% (95% CI, 18.6%-53.2%), specificity of 99.9% (95% CI, 99.9%-100.0%), positive LR of 3088.9 (95% CI, 410.8-23 226.7), and negative LR of 0.7 (95% CI, 0.5-0.8). The positive and negative predictive values of the 2-primer DBS PCR were 91.7% (95% CI, 61.5%-99.8%) and 99.8% (95% CI, 99.6%-99.9%), respectively.
  
  
  CONCLUSIONS
  Among newborns, CMV testing with DBS real-time PCR compared with saliva rapid culture had low sensitivity, limiting its value as a screening test.
authors.affiliation: UAB Department of Pediatrics, CHB 114, 1600 Sixth Ave S, Birmingham, AL 35233, USA. sboppana@peds.uab.edu
authors.forename: Suresh B
authors.initials: SB
authors.lastname: Boppana
authors.forename: Shannon A
authors.initials: SA
authors.lastname: Ross
authors.forename: Zdenek
authors.initials: Z
authors.lastname: Novak
authors.forename: Masako
authors.initials: M
authors.lastname: Shimamura
authors.forename: Robert W
authors.initials: RW
authors.lastname: Tolan
authors.forename: April L
authors.initials: AL
authors.lastname: Palmer
authors.forename: Amina
authors.initials: A
authors.lastname: Ahmed
authors.forename: Marian G
authors.initials: MG
authors.lastname: Michaels
authors.forename: Pablo J
authors.initials: PJ
authors.lastname: Sánchez
authors.forename: David I
authors.initials: DI
authors.lastname: Bernstein
authors.forename: William J
authors.initials: WJ
authors.lastname: Britt
authors.forename: Karen B
authors.initials: KB
authors.lastname: Fowler
mesh_terms: D003587:Cytomegalovirus / Q000235:genetics / Q000302:isolation & purification*; D003586:Cytomegalovirus Infections / Q000151:congenital* / Q000175:diagnosis*; D004279:DNA, Viral / Q000032:analysis; D006801:Humans; D007231:Infant, Newborn; D015997:Neonatal Screening; D016133:Polymerase Chain Reaction / Q000379:methods* / Q000592:standards; D015203:Reproducibility of Results; D012463:Saliva / Q000821:virology; D012680:Sensitivity and Specificity
chemical_list: D004279:DNA, Viral
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