Skip to main content

Table 2 Cp values of the 62a truly PCR-positive but culture-negative clinical specimens

From: Comparison of an automated DNA extraction and 16S rDNA real time PCR/sequencing diagnostic method using optimized reagents with culture during a 15-month study using specimens from sterile body sites

Cp value < 22.5 22.5-25.00 25.01-27.5 27.51-30 30.01-32.5 32.51-35.00
Number 2 8 6 17 20 8
  1. The diluted positive control (with approx. 100 genome copies/PCR) has a Cp of ~ 31, indicating that only very few (8, i.e., 13%) clinical specimens contain bacterial DNA at the detection limit. The remaining clinical specimens (87%) were abundantly clearly positive. a1 Cp value was retrospectively not available (and is therefore not listed). Negative controls contained no specific amplification product (above 84 °C). For 15 clinical specimens with positive PCR but negative culture information regarding antibiotics were available (13 were treated with an antibiotic, 2 were without an antibiotic). Out of these 13 clinical specimens, 7 had low amount of pathogen DNA (indicated by maximal volume (in μL) of PCR product needed for sequencing)