Download East to use real time PCR test for CT & NG

An easy to use real time PCR test for Chlamydia trachomatis and
Neisseria gonorrhoeae providing results that can guide treatment
choices before the patient leaves the clinic
Charlotte A. Gaydos, MS, MPH, DrPH1, Barbara Van Der Pol, MPH, PhD2,3, Mary Jett- Goheen, BS1, Mathilda
Barnes, MS1, Nicole Quinn, BS1, Carey Clark3, Grace E. Daniel3, Paula B. Dixon3, Edward W. Hook III, MD3
1
1 Division
of Infectious Diseases, Medicine, Johns Hopkins, Baltimore, Maryland, 2 Indiana University School of Public Health, Dept Epidemiology
& Biostatistics, Bloomington, Indiana, 3Indiana University School of Medicine, Division of Infectious Diseases, Indianapolis, Indiana 3 University
of Alabama at Birmingham and Jefferson County Health Department, Birmingham, Alabama
Background
Results
• New diagnostics for Chlamydia trachomatis
(CT) and Neisseria gonorrhoeae (NG) that can
provide accurate, rapid, and timely results are
urgently needed so that patients can be
treated at the time they visit a clinic.
• The Cepheid GeneXpert® (Xpert) CT/NG
assay is a rapid nucleic acid amplification test
(NAAT) assay that can be performed in on-site
laboratories.
• The assay detects DNA of CT and NG from
female endocervical, patient-collected
vaginal, and urine specimens, and in male
urine from symptomatic and asymptomatic
individuals.
Methods
• The Xpert test is a modular, cartridge-based,
“walk-away” platform for testing which
requires no manipulation from specimen
loading until results are available (90 minutes).
CHLAMYDIA
ASSAY
Female
Endocervix
Female
Vaginal
Female Urine
Sensitivity
Specificity
97.4%
99.6%
98.7%
99.4%
97.6%
99.8%
Male Urine
97.5%
99.9%
GONORRHEA
ASSAY
Female
Endocervix
Female
Vaginal
Female Urine
Sensitivity
Specificity
100%
100%
100%
99.9%
95.6%
99.9%
Male Urine
97.5%
99.9%
• We compared results from the Xpert assay to
results from two currently approved nucleic
acid amplification assays (Aptima Combo2 and
ProbeTec) in 1,722 females and 1,387 males.
• The targets were two highly conserved, noncontiguous NG-unique chromosomal targets
for NG and a chromosomal CT target.
• The Xpert assay includes a specimen adequacy
control (SAC) result and a specimen
processing control (SPC) result.
• A patient infected status (PIS) was determined
for each sample type.
• The PIS for each specimen type was
considered infected if a minimum of one
positive result was reported by each of the two
comparator NAAT assays for that specimen
type (at least one from each comparator assay).
Comparisons of positive test results for Cepheid
Xpert CTNG (GX), Becton Dickinson ProbeTec (BD),
and GenProbe Aptima Combo2 (GP) for male and
female urine, and female endocervical specimens for
Chlamydia trachomatis and Neisseria gonorrhoeae
Conclusions
• The GeneXpert® System is a closed, selfcontained, fully-integrated, automated
platform for CT/NG testing that demonstrated
excellent sensitivities and specificities in
women and men.
• This relatively rapid short-turn-around-test can
provide results to guide treatment decisions
before patients leave the clinical setting. Such
rapid treatment could potentially improve
chlamydia and gonorrhea control efforts.
Bibliography
Assay time: ~90 Minutes
Gaydos CA, et al JCM 51:1666-1672, 2013
Tabrizi et al. JCM 51:1945-1947, 2013