TY - JOUR
T1 - Association of the CT values of real-time PCR of viral upper respiratory tract infection with clinical severity, Kenya
AU - Fuller, James A.
AU - Njenga, M. Kariuki
AU - Bigogo, Godfrey
AU - Aura, Barrack
AU - Ope, Maurice O.
AU - Nderitu, Leonard
AU - Wakhule, Lilian
AU - Erdman, Dean D.
AU - Breiman, Robert F.
AU - Feikin, Daniel R.
N1 - Copyright:
Copyright 2013 Elsevier B.V., All rights reserved.
PY - 2013/5
Y1 - 2013/5
N2 - Quantitative real-time polymerase chain reaction (qRT-PCR) assay of the upper respiratory tract is used increasingly to diagnose lower respiratory tract infections. The cycle threshold (CT) values of qRT-PCR are continuous, semi-quantitative measurements of viral load, although interpretation of diagnostic qRT-PCR results are often categorized as positive, indeterminate, or negative, obscuring potentially useful clinical interpretation of CT values. From 2008 to 2010, naso/oropharyngeal swabs were collected from outpatients with influenza-like illness, inpatients with severe respiratory illness, and asymptomatic controls in rural Kenya. CT values of positive specimens (i.e., CT values<40.0) were compared by clinical severity category for five viruses using Mann-Whitney U-test and logistic regression. Among children <5 years old we tested with respiratory syncytial virus (RSV), inpatients had lower median CT values (27.2) than controls (35.8, P=0.008) and outpatients (34.7, P<0.001). Among children and older patients infected with influenza virus, outpatients had the lowest median CT values (29.8 and 24.1, respectively) compared with controls (P=0.193 for children, P<0.001 for older participants) and inpatients (P=0.009 for children, P<0.001 for older participants). All differences remained significant in logistic regression when controlling for age, days since onset, and coinfection. CT values were similar for adenovirus, human metapneumovirus, and parainfluenza virus in all severity groups. In conclusion, the CT values from the qRT-PCR of upper respiratory tract specimens were associated with clinical severity for some respiratory viruses. J. Med. Virol. 85:924-932, 2013.
AB - Quantitative real-time polymerase chain reaction (qRT-PCR) assay of the upper respiratory tract is used increasingly to diagnose lower respiratory tract infections. The cycle threshold (CT) values of qRT-PCR are continuous, semi-quantitative measurements of viral load, although interpretation of diagnostic qRT-PCR results are often categorized as positive, indeterminate, or negative, obscuring potentially useful clinical interpretation of CT values. From 2008 to 2010, naso/oropharyngeal swabs were collected from outpatients with influenza-like illness, inpatients with severe respiratory illness, and asymptomatic controls in rural Kenya. CT values of positive specimens (i.e., CT values<40.0) were compared by clinical severity category for five viruses using Mann-Whitney U-test and logistic regression. Among children <5 years old we tested with respiratory syncytial virus (RSV), inpatients had lower median CT values (27.2) than controls (35.8, P=0.008) and outpatients (34.7, P<0.001). Among children and older patients infected with influenza virus, outpatients had the lowest median CT values (29.8 and 24.1, respectively) compared with controls (P=0.193 for children, P<0.001 for older participants) and inpatients (P=0.009 for children, P<0.001 for older participants). All differences remained significant in logistic regression when controlling for age, days since onset, and coinfection. CT values were similar for adenovirus, human metapneumovirus, and parainfluenza virus in all severity groups. In conclusion, the CT values from the qRT-PCR of upper respiratory tract specimens were associated with clinical severity for some respiratory viruses. J. Med. Virol. 85:924-932, 2013.
KW - Influenza
KW - PCRl
KW - Respiratory syncytial virus
KW - Viral pneumonial
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U2 - 10.1002/jmv.23455
DO - 10.1002/jmv.23455
M3 - Article
C2 - 23508918
AN - SCOPUS:84875654749
SN - 0146-6615
VL - 85
SP - 924
EP - 932
JO - Journal of Medical Virology
JF - Journal of Medical Virology
IS - 5
ER -