42 |
Klinisk Biokemi i Norden · 1 2018
Summary of an evaluation
organised by SKUP
Elisabet Eriksson Boija and Grete Monsen, on behalf of SKUP
Background
QuickVue Dipstick Strep A Test is a rapid test for
detection of
Streptococcus pyogenes
group A (Strep A)
in patient throat samples. The test is produced by Qui-
del Corporation, which also requested the evaluation.
QuickVue Dipstick Strep A Test has been evaluated
previously by SKUP (2003), but only with Strep A refe-
rence strains in a clinical microbiology laboratory. The
present evaluation also includes genuine throat swab
samples from primary health care centres.
The aim of the evaluation
The aim of the evaluation was to determine the analyti-
cal quality and user-friendliness of QuickVue Dipstick
Strep A Test.
Materials and methods
The evaluation was carried out in a clinical microbio-
logy laboratory and by intended users at seven primary
health care centres. The results were assessed accor-
ding to pre-set quality goals.
In the clinical microbiology laboratory, two types of
evaluations were performed:
1. The throat swab samples from patients from the
seven primary health care centres were analysed
with the comparison method (culturing).
2. Dilution series of a Strep A reference strain, five
Strep A patient strains, one Strep C strain, one Strep
G strain were analysed with QuickVue Dipstick
Strep A test. Inter-person reading agreement was
examined by comparing the results from two evalua-
tors reading all samples double-blinded. Robustness
of the test result was also investigated by re-reading
the results from the least and the most diluted samp-
les of each strain five minutes after recommended
reading time. As an additional experiment, the
throat swab samples were analysed with real-time
polymerase chain reaction (real-time PCR).
In the seven primary health care centres, two throat
swabs were taken from all consenting patients with
symptoms of bacterial throat infection (n = 322); one
swab for direct measurement with QuickVue Dipstick
Strep A Test, and the other to be sent to the clinical
microbiology laboratory for culturing.
Number of true positive results
Number of false negative results
Diagnostic sensitivity
107
9
92%
Number of true negative results
Number of false positive results
Diagnostic specificity
164
27
86%
QuickVue Dipstick Strep A Test
