Results of EQA for PCR.

Table 5 shows results of external quality assurance for PCR. During the initial phase (phase I) PCR samples were analyzed at DITM by IS2404 standard PCR and IS2404 quantitative real-time PCR (qPCR). During the transitional phase (phase II) diagnostic sample pairs where analyzed in parallel at INH (IS2404 dry-reagent-based [DRB] PCR) and DITM as described for phase I. Positivity rates and case confirmation rates are provided for IS2404 DRB- and standard PCR, and additional diagnostic yields were calculated for IS2404 qPCR. N/A, not applicable.
aSwab samples, DNA extract were prepared from swab samples.
bFNA samples, DNA extract were prepared from fine-needle aspirate samples.
cPunch samples, DNA extract were prepared from 3-mm punch biopsy samples.
dTotal per phase and laboratory.
eINH applied IS2404-DRB-PCR. [21]
fDITM applied standard, gel-based, IS2404 PCR [17] and IS2404 qPCR [27], [42] on all DNA extracts tested negative with standard PCR. For qPCR the additional diagnostic yield (i.e. the deviation of total final result from total result of standard PCR) were 5.7% (phase I) and 6.1% (phase II).
gFinal result of standard PCR and qPCR.
hPhase I, initial phase of implementation of the national reference laboratory at INH from September through December 2010.
iPositivity rate, number of positive samples divided by the total number of samples tested.
jCase confirmation rate, number of laboratory confirmed BUD patients divided by the total number of suspected BUD cases.
kRate of false negative results at INH as determined by re-testing of DNA extracts at DITM by standard PCR.
lRate of concordant results from sample pairs at INH and DITM.
mPhase II, transitional phase of implementation of the national reference laboratory at INH from January 2011 through April 2012.
nTotal results of the initial and the transitional phase.