Cross-contamination During Processing of Dried Blood Spots Used for Rapid Diagnosis of HIV-1 Infection of Infants Is Rare and Avoidable

J Virol Methods. 2010 Feb;163(2):489-91. doi: 10.1016/j.jviromet.2009.10.016. Epub 2009 Oct 28.

Abstract

Dried blood spot (DBS) samples are a convenient way to collect infant blood for HIV-1 diagnostic testing. Minimizing the risk of false positives is critical for diagnostic tests. A protocol for processing and testing DBS for infant HIV-1 diagnosis was evaluated to identify the rate and source of false-positive results. DBS were created on Flinders Technology Associates (FTA) filter paper with 500 copies/punch (high) or 5000 copies/punch (very high) concentrations of HIV-1 DNA. Blank discs of filter paper punched after DBS samples were tested for carry-over of HIV-1 DNA using nested PCR for the pol region. No false positives were detected in the 40 series using high concentration DBS. In series with very high concentrations of HIV-1, 8/246 (3%) reactions were falsely positive. When tubes were spun prior to opening, contact with caps minimized, and spaces left between lanes of the gel, repeat second-round PCR of five false positives resulted in only one repeat false-positive PCR. This study outlines procedures that minimize false-positive results for nested PCR of HIV-1 DNA from DBS.

Publication types

  • Evaluation Study
  • Research Support, N.I.H., Extramural

MeSH terms

  • Blood / virology*
  • DNA, Viral / isolation & purification
  • Desiccation*
  • False Positive Reactions*
  • HIV Infections / diagnosis*
  • HIV-1 / isolation & purification*
  • Humans
  • Infant
  • Infant, Newborn
  • Polymerase Chain Reaction / methods
  • Sensitivity and Specificity
  • Specimen Handling / methods*

Substances

  • DNA, Viral