Diesse Chorus - Avidity

Manuale operativo CHORUS
Rev. 0 del 06/2012 97
R% = (T
5
- T
6
) *100
10 ng/ml
5.3.5.2 Quality control
The verification routine of the QC involves processing the QC of a test batch with the corresponding
strip in the standard mode, as any sample.
Once the optical density of the QC has been determined,
OD
QC
= OD3 – OD1
Calculate
I
QC
= OD
QC
/ OD
cal
And verify whether:
I
upper
≥ I
QC
≥ I
lower
Where the limits I
upper
and I
lower
are reported in the QC barcode.
If I
QC
is within the limits, the QC is accepted; otherwise, it is rejected and in the final report the warning
sign “!“ is printed .
In any case the titer is supplied by the CC, while the indication of positive/negative/doubt (P/N/D) is
determined in reference to the calibrator.
5.3.6 A VIDITY
The Avidity test is carried out as a result of a positive IgG test and has the scope to determine the % of
Avidity.
No calibration is needed for this test. It is carried out comparing the values calculated in the two
measure wells (5 and 6) where two reactions have been started both with unknown serum, but one of
them with the addition of a urea based reagent (urea) (well5) and the other with the Cleaning solution
only.
At the end of the analytical process three readings are obtained in well 5: OD1u, OD2u, OD3u and
three readings in well 6: ODr1, ODr2, ODr3.
The optical density of the urea is calculated
OD
urea
= OD3u – OD1u
And that of the reference
OD
ref
= OD3r – OD1u
The OD of the reference is then compared in the following way:
If OD
ref
< AVC
then the sample cannot be calculated (NC) and is defined as Negative IgG and the calculation ends.
(AVC is a parameter from the methods)
If OD
ref
> 1800
then the sample is said to be strongly positive IgG (Dil 1:3.) The sample is defined as To dilute 1:3
and the calculation ends.