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Aiding in the diagnosis of adenovirus infections
Human adenoviruses cause a variety of diseases including pneumonia, cystitis, conjunctivitis, diarrhea, hepatitis, myocarditis, and encephalitis. In humans, adenoviruses have been recovered from almost every organ system. Infections can occur at any time of the year and in all age groups. Currently, there are 51 adenovirus serotypes that have been grouped into 6 separate subgenera.
Culture is the gold standard for the diagnosis for adenovirus infection. However, it can take up to 3 weeks to achieve culture results (Mayo Clinic's shell vial culture provides more rapid results, reported at 2 and 5 days). Serological tests have faster turnaround times, but can be less sensitive compared to culture. PCR offers a rapid, specific, and sensitive means of diagnosis by detecting adenovirus DNA.
A positive result indicates the presence of adenoviruses.
A negative result does not rule out the presence of adenoviruses because organisms may be present at levels below the detection limits of this assay.
Test results should be used as an aid in diagnosis and should not be considered diagnostic in themselves.
Although the reference range is generally considered to be "Negative" for this assay, adenovirus DNA may be detected from asymptomatic individuals in certain settings. This assay should only be used to test patients with clinical history and symptoms consistent with adenovirus disease, and is not used to screen healthy patients.
The following support the use of this assay for clinical testing.
Accuracy/Diagnostic Sensitivity and Specificity:
A study of 715 clinical specimens compared shell vial culture and this PCR assay. Included in the study were 286 swab specimens (nasal, throat, rectal, skin), 49 eye specimens, 221 respiratory specimens (bronchial washings, sputa, bronchioalveolar lavage, tracheal secretions), 55 fresh tissue specimens, 72 stools, and 27 body fluids/other specimens. Specimens were inoculated into culture tubes and examined for cytopathic effects over a period of 14 days, and subsequently assayed with this LightCycler assay. Comparison of cell culture with LC PCR yielded the following: total specimens positive by LC PCR was 60 (stool=9; respiratory=4; tissue=4; swabs=24; eye specimens=14; and urine=4) and total specimens by culture were 52 (stool=8; respiratory=3; tissue=3; swabs=23; eye specimens=13; and urine=2). Of the 60 total positive specimens, PCR produced a 13.5% increased rate of detection of adenovirus compared with culture. This assay detected all 51 serotypes of adenovirus tested.
Supplemental Data (Spiking Studies):
To supplement the above data, 30 negative specimens of various types (CSF, ocular, respiratory, stool, urine, and plasma) were spiked with adenovirus positive control plasmid at the limit of detection (approximately 10 targets/microliter). The 30 spiked specimens were run in a blinded manner with 30 negative (nonspiked) specimens. 100% of the spiked specimens were positive and 100% of the nonspiked specimens were negative.
Analytical Sensitivity/Limit of Detection (LoD):
The LoD of this assay is 10 targets per microliter in specimen matrix.
No PCR signal was obtained from extracts of 150 bacterial, viral, parasitic, and fungal isolates that could cause similar disease or could be found as normal flora in sites normally tested for this organism.
Interassay precision was 100% and intra-assay precision was 100%.
The reference range is "negative" for this assay.
This is a qualitative assay and results are reported as negative or positive for targeted adenovirus DNA.
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2. Ebner K, Suda M, Watzinger F, Lion T: Molecular detection and quantitative analysis of the entire spectrum of human adenoviruses by a two-reaction real-time PCR assay. J Clin Microbiol 2005;43:3049-3053
3. Jothikumar N, Cromeans TL, Hill VR, et al: Quantitative real-time PCR assays for the detection of human adenoviruses and identification of serotypes 40 and 41. Appl Environ Microbiol 2005;71:3131-3136
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