Diesse CHORUS dsDNA-M Mode D'emploi page 8

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Normal laboratory glassware: cylinders, test-tubes etc.
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Micropipettes for the accurate collection of 50-200 µl
solution
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Disposable gloves
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Sodium Hypochlorite solution (5%)
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Containers for collection of potentially infectious materials
6. STORAGE AND STABILITY OF REAGENTS
Reagents must be stored at 2/8°C. In the case of storage
at an incorrect temperature the calibration must be
repeated and the run validated using the control serum
(see section 9, Test validation).
The expiry date is printed on each component and on the
kit label.
Reagents have a limited stability after opening:
DEVICES 8 weeks at 2/8°C
CALIBRATOR 8 weeks at 2/8°C
POSITIVE CONTROL 8 weeks at 2/8°C
7. SPECIMEN COLLECTION AND STORAGE
The sample is composed of serum collected from the vein and
handled with all precautions dictated by good laboratory
practice.
According to the guideline CLSI H18-A3 Serum specimens to
be tested should be clotted before centrifugation; spontaneous
and complete clotting normally occurs within 30 to 60 minutes
at 22°C-25°C.
It is recommended that serum be physically separated, by
centrifugation, from contact with cells as soon as possible with
a maximum time limit of 2 hours from the time of collection.
Possible consequences, in case of use of other biological
liquids, are not known.
The fresh serum may be stored for 4 days at 2/8°C, or frozen
for longer periods at temperature ≤ –20°C for 69 months and
can be thawed a maximum of 3 times.
Do not keep the samples in auto-defrosting freezers.
Defrosted samples must be shaken carefully before use.
Heat-inactivation can rise to erroneous results.
The quality of the sample can be seriously affected by microbial
contamination which leads to erroneous results.
8. ASSAY PROCEDURE
1. Open the package (on the side containing the pressure-
closure), remove the number of devices required and seal
the rest in the bag after expelling the air.
2. Check the state of the device according to the indications
reported in chapter 4, Analytical Precautions.
3. Dispense 50 µl of undiluted test serum in well no. 1 of
each device; at each change of batch, use a device for the
calibrator.
4. Place the devices in the Chorus/Chorus TRIO instrument.
Perform the calibration (if necessary) and the test as
reported in the instrument Operating Manual.
9. TEST VALIDATION
Use the control serum to check the validity of the results
obtained. It should be used as reported in the instrument
Operating Manual. If the instrument signals that the control
serum has a value outside the acceptable range, the calibration
must be repeated. The previous results will be automatically
corrected.
If the result of the control serum continues to be outside the
acceptable range, contact the Customer care .
Tel: 0039 0577 319554
email: scientificsupport@diesse.it
customercare@diesse.it
10. INTERPRETATION OF THE RESULTS
The Chorus/Chorus TRIO instrument expresses the result in
Arbitrary Units (AU/ml) calculated on the basis of a lot-
dependent graph stored in the instrument.
The test on the examined serum can be interpreted as follows:
POSITIVE: when the result is > 30.0
NEGATIVE: when the result is < 20.0
DOUBTFUL/EQUIVOCAL: for all values between 20.0 and 30.0
If the result is doubtful/equivocal, repeat the test. If it remains
doubtful/equivocal, collect a new serum sample.
11. LIMITATIONS
All the values obtained require a careful interpretation that must
consider other indicators relative to the patient.
The test, indeed, can not be used alone for a clinical diagnosis
and the test result should be evaluated together with the patient
history and other clinical diagnostic evaluation.
12. CALIBRATION RANGE
Calibration range 10.0 - 150.0 AU/ml.
For samples > 150.0 AU/ml retest the diluted sample in the
Negative Control/Sample Diluent (PF83607-not supplied with
the kit).
13. ANALITICAL SPECIFICITY
5 samples (2 Negative, 1 Cut-Off and 2 Positive) were spiked
with the following potentially interfering factors and then tested:
Rheumatoid factor (44-220 IU/ml)
Bilirubin (4.5-45 mg/dl)
Triglycerides (10-250 mg/dl)
Hemoglobin (5-30 mg/ml)
The presence in the serum sample of the interfering substances
described above does not affect the test result.
14. CROSS-REACTIONS
22 samples, positive to ASCA, CCP, Cenp-B, GBM, Gliadin, Jo-
1, MPO, PR3, RF, U1-70 RNP, Scl-70, Sm, SS-A, SS-B, tTg
were tested.
No significant cross-reactions were found.
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