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External Quality Assessment for the Detection of Chlamydia trachomatis in Urine Using Molecular Techniques in Belgium.

China B, Vernelen K - J Sex Transm Dis (2015)

Bottom Line: The EQA panels included positive and negative samples.Two major issues were observed: the low sensitivity (45.3%) for the detection of low concentration samples and the incapacity of several methods to detect the Swedish variant of C. trachomatis.The reassuring point was that the overall proficiency of the Belgian laboratories tended to improve over time.

View Article: PubMed Central - PubMed

Affiliation: Quality of Medical Laboratories, Scientific Institute of Public Health, J. Wytsman 14, 1050 Brussels, Belgium.

ABSTRACT
Chlamydia trachomatis is a major cause of sexually transmitted bacterial disease worldwide. C. trachomatis is an intracellular bacterium and its growth in vitro requires cell culture facilities. The diagnosis is based on antigen detection and more recently on molecular nucleic acid amplification techniques (NAAT) that are considered fast, sensitive, and specific. In Belgium, External Quality Assessment (EQA) for the detection of C. trachomatis in urine by NAAT was introduced in 2008. From January 2008 to June 2012, nine surveys were organized. Fifty-eight laboratories participated in at least one survey. The EQA panels included positive and negative samples. The overall accuracy was 75.4%, the overall specificity was 97.6%, and the overall sensitivity was 71.4%. Two major issues were observed: the low sensitivity (45.3%) for the detection of low concentration samples and the incapacity of several methods to detect the Swedish variant of C. trachomatis. The reassuring point was that the overall proficiency of the Belgian laboratories tended to improve over time.

No MeSH data available.


Related in: MedlinePlus

Parameters per survey. Ac: accuracy; Se: sensitivity; Sp: specificity.
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fig1: Parameters per survey. Ac: accuracy; Se: sensitivity; Sp: specificity.

Mentions: The overall number of Belgian results was 2917. The returned results were always qualitative (presence or absence) results. The number of correct results (accuracy) was 2198/2917 (75.4%). The number of incorrect results was 719/2917 (24.6%). Of the incorrect results, the number of false positive results was 6/719 (0.8%) and the number of false negative results was 693/719 (96.4%). The number of inhibition results was 20/719 (2.8%). The number of negative and frequently detected samples was 445 and 747, respectively. The number of clinically relevant faults was 61/1192 (5.1%) including 6/445 (1.3%) false positive and 55/747 (7.4%) false negative. The overall sensitivity and specificity were 71.4% (1764/2472) and 97.6% (434/445), respectively. When the yearly evolution was considered (Figure 1), a general increase both in sensitivity and in specificity was observed from 2008 to 2012. For the 2011-1 survey, a decrease in sensitivity was observed partially due to the presence of a sample with a very low copy number (CTADNA11-01).


External Quality Assessment for the Detection of Chlamydia trachomatis in Urine Using Molecular Techniques in Belgium.

China B, Vernelen K - J Sex Transm Dis (2015)

Parameters per survey. Ac: accuracy; Se: sensitivity; Sp: specificity.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4496476&req=5

fig1: Parameters per survey. Ac: accuracy; Se: sensitivity; Sp: specificity.
Mentions: The overall number of Belgian results was 2917. The returned results were always qualitative (presence or absence) results. The number of correct results (accuracy) was 2198/2917 (75.4%). The number of incorrect results was 719/2917 (24.6%). Of the incorrect results, the number of false positive results was 6/719 (0.8%) and the number of false negative results was 693/719 (96.4%). The number of inhibition results was 20/719 (2.8%). The number of negative and frequently detected samples was 445 and 747, respectively. The number of clinically relevant faults was 61/1192 (5.1%) including 6/445 (1.3%) false positive and 55/747 (7.4%) false negative. The overall sensitivity and specificity were 71.4% (1764/2472) and 97.6% (434/445), respectively. When the yearly evolution was considered (Figure 1), a general increase both in sensitivity and in specificity was observed from 2008 to 2012. For the 2011-1 survey, a decrease in sensitivity was observed partially due to the presence of a sample with a very low copy number (CTADNA11-01).

Bottom Line: The EQA panels included positive and negative samples.Two major issues were observed: the low sensitivity (45.3%) for the detection of low concentration samples and the incapacity of several methods to detect the Swedish variant of C. trachomatis.The reassuring point was that the overall proficiency of the Belgian laboratories tended to improve over time.

View Article: PubMed Central - PubMed

Affiliation: Quality of Medical Laboratories, Scientific Institute of Public Health, J. Wytsman 14, 1050 Brussels, Belgium.

ABSTRACT
Chlamydia trachomatis is a major cause of sexually transmitted bacterial disease worldwide. C. trachomatis is an intracellular bacterium and its growth in vitro requires cell culture facilities. The diagnosis is based on antigen detection and more recently on molecular nucleic acid amplification techniques (NAAT) that are considered fast, sensitive, and specific. In Belgium, External Quality Assessment (EQA) for the detection of C. trachomatis in urine by NAAT was introduced in 2008. From January 2008 to June 2012, nine surveys were organized. Fifty-eight laboratories participated in at least one survey. The EQA panels included positive and negative samples. The overall accuracy was 75.4%, the overall specificity was 97.6%, and the overall sensitivity was 71.4%. Two major issues were observed: the low sensitivity (45.3%) for the detection of low concentration samples and the incapacity of several methods to detect the Swedish variant of C. trachomatis. The reassuring point was that the overall proficiency of the Belgian laboratories tended to improve over time.

No MeSH data available.


Related in: MedlinePlus