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VIDAS LPT - Summary 2012
EUROFINS IPL Nord SAS
–
1 rue du Professeur Calmette
–
59046 LILLE cedex
p 14/14
10.
Type of operator qualification
Identical level to that required for reference method
11.
Common steps with reference
method
Confirmations
12.
Analysis result traceability
A results sheet is printed mentioning the reagent references, the date and
time, the test result and the sample identification.
13.L
aboratory maintenance
The VIDAS user manual explains some problems.
Telephone technical support from bioMérieux. Preventive maintenance
contracts available.
5 General conclusion
The comparative study of the methods was performed according to the EN ISO 16140:2003 reference.
The performances of the VIDAS
LPT method were compared to those of the EN ISO 11290-1 reference method
(including the amendment A1) by analyzing 345 samples divided into five product categories.
The relative accuracy obtained for the VIDAS
LPT method is 91.9%, the relative sensitivity is 90.4% and the
relative specificity is 93.1%, based on the calculations stipulated by the EN ISO 16140 standard.
Based on the calculations recommended by AFNOR, and based on the number of results selected, the sensitivity
of the VIDAS LPT method is 91.2%. That of the reference method is 92.4%.
Finally, both methods are considered to be statistically equivalent.
The storage of the enrichment LPT broths after incubation, for 72 hours at 2-8°C, did not modify the performances
of the method.
The level of detection obtained for the alternative method is between 0.3 and 1.1 cells per 25 g or 25 mL. It is close
to that of the reference method (0.3 and 1.5 cells per 25 g or 25 ml).
The specificity of the method is satisfactory, all
Listeria
strains were detected and no cross-reaction was observed
with non-target strains
The results of the inter-laboratory study obtained for all 14 laboratories selected demonstrate that the alternative
method has globally higher relative accuracy, specificity and sensitivity values than that of the reference method,
even though they are not in the same level as those obtained in the preliminary study.
The sensitivity of the alternative method recalculated accounting for all the confirmed positives (including the
additional positives from the alternative method) is also higher than that obtained in the preliminary study (93.8% /
90.4%).
Both methods did not appear to be statistically different (McNemar test).
The variability of the alternative method (accordance, concordance, odds ratio) is comparable to that of the
reference method.
On the basis of all the results obtained according to the EN ISO 16140 (2003) standard, it was possible to grant the
NF VALIDATION certification
to the VIDAS
®
UP
Listeria
(VIDAS
®
LPT) method for the detection of
Listeria
spp. in
food products for humans and environment samples (excluding primary production samples), with the certificate
number BIO 12/33
–
05/12.
Lille, le 13 février 2012
Mélinda Maux
Responsable Etudes