Dec 1, 2012 ... 6-point calibration curve as defined in the instrument manuals. Calibrator values
... The Gentian Cystatin C Immunoassay was used in a 5-days.
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Application Note for Gentian Cystatin C Immunoassay on BS3801, Mindray1 Using Calibrator (REF1012) Intended Use The Gentian Cystatin C Immunoassay is an in vitro diagnostic test for quantitative determination of cystatin C in human serum and plasma. The measurement of cystatin C is used in the diagnosis and treatment of renal disease.
Measuring range
For in vitro diagnostic use only © v01en – December 2012
Calibrator The calibrator is ready to use. Assay Buffer (R1) The Gentian Cystatin C Assay Buffer is the Reaction Buffer R1. The buffer is ready for use.
The overall measuring range of cystatin C concentration for Gentian Cystatin C Immunoassay on the BS3801 analyser is approximately 0.23-7.50 mg/L.
Immunoparticles (R2) The Gentian Cystatin C Immunoparticles are ready for use.
Reference intervals
All reagents are stable until the expiry date given on the labels when stored at 2-8ºC.
Gentian followed the CLSI Guideline, C28-A2 to determine the transferability of the reference interval. The reference interval was determined from a population of ostensibly healthy subjects with no history of renal disease. A total of 136 samples obtained from 58 males and 80 females ranging in age from 20 to 80 years were tested. The reference interval was calculated non-parametrically and was determined to be 0.57-1.09 mg/L on AU4002 Beckman Coulter2, This represents the central 95 % of the population. It is recommended that every laboratory should determine a local reference interval since values may vary depending on the population tested. In a separate study involving 850 healthy children (46% boys, 54 % girls) in the age from 5 to 15 years, the reference range 0.51 - 1.05 mg/L was confirmed in all ages down to 5 years of age [1].
GFR prediction calculation Several cystatin C based prediction equations for calculation of GFR for adults and children have been published. It should be noted that these formulas were evaluated with different Cystatin C assays (particle-enhanced nephelometric immunoassay PENIA or particle enhanced turbidimetric immunoassay PETIA) and may reveal inaccurate GFR results if an inappropriate combination of formula and assay is used. For calculation of GFR from cystatin C values measured with the Gentian assay the following prediction equation is recommended using mg/L as the unit factor [2]: The equation is valid for persons above 14 years.
Cystatin C (mg/L)1.4389
Assay Reagents Materials Provided by Gentian AS: Gentian Cystatin C Reagent Kit
REF 1101
Gentian Cystatin C Calibrator, 1 level, vial of 1 ml
REF 1012
Gentian Cystatin C Calibrator Kit, 6 levels, vials of 1 ml
REF 1051
Gentian Cystatin C Control Kit, 2 vials of 1 ml
REF 1019
Gentian Cystatin C Control Kit, 2 vials of 5 ml
REF 1026
All materials are ready for use.
Calibration Stability The established calibration curve is stable for 4 weeks on BS3801. When reagent lots are changed or measured control values are outside the assigned range given in the Analytical Value Sheet, a recalibration is recommended. On board Stability In appropriate bottles, Gentian Cystatin C Immunoparticles and Assay Buffer are stable for at least 9 weeks when stored on board the analyser.
Specimen Required sample material is human serum, heparinized plasma and EDTA plasma. It is recommended to analyse the samples as fresh as possible. Sample stability testing showed that cystatin C in serum and plasma samples are stable for 14 days at room temperature (8-25ºC), 21 days if stored at 2-8ºC and stored at below -20ºC for at least 10 years [3]. Mix samples well before analysing. The samples can be shipped without special cooling and must then be analysed within 14 days after shipment.
Procedure Application Notes/Assay Installation An Instrument Parameter list is available in the section “Instrument Settings” below. The Application Note is also available at www.gentian.no. Instrument set up, maintenance, operation and precautions must be handled in accordance with the instrument manuals.
79.901
2
GFR [mL/min/1.73 m ] =
Calibrator Standardisation Gentian Cystatin C Calibrator is standardised against the international calibrator standard ERM-DA471/IFCC.
Loading of Reagents Reagents are supplied ready to use. Transfer the content of R1 and R2 into appropriate channel bottles if necessary, mix well before transfer. Use care to avoid contamination. Reagents shall be stored capped at 2-8°C when not in use. Calibration curve establishment Use Gentian Cystatin C Calibrator, REF1012, with the auto dilution settings listed in 'Instrument Settings' below to establish a 6-point calibration curve as defined in the instrument manuals. Calibrator values are lot dependent and a new calibration must be performed whenever a new calibration lot is used. The calibrator’s assigned values are given in the analytical value sheet provided with the calibrator.
Application Note for Gentian Cystatin C Immunoassay on BS3801, Mindray1
v01-December 2012
Page 2 of 4 QC Controls The controls low and high must be assayed each day before any samples are assayed in order to validate the calibration curve. The controls have an assigned value range that must be met before measuring samples. The assigned values are given in the Analytical Value sheet included with the Gentian Cystatin C Control Kit (REF1019 or REF1026). If the control values are not valid, repeat the control measurements. If the calibration cannot be performed without error, or valid control values cannot be reproduced, contact the manufacturer for support. Measuring Patient Samples When a valid calibration has been performed and the control values are within the valid range, serum or plasma samples may be measured. Check that minimum sample is present and assay the samples according to the instructions given in the Instrument Manuals. Results The results are calculated automatically by the analyser and are presented in mg/L.
CLSI [5]. There is no RF interference present in the Gentian Cystatin C Immunoassay because the antibodies are made from avian (chicken) [6]. Method Comparison Results obtained with the Gentian Cystatin C Immunoassay on BS3801 when compared by Passing-Bablok regression to Gentian cystatin C Immunoassay on Beckman Coulter, AU400. Method
N
Range specimen (mg/L)
37
0.70–4.44
1
BS380 vs 2 AU400
Term
Coefficient
Intercept
0.14
Slope
0.90
Shipping damage Please notify your distributor if this product is received damaged.
Symbols Key
Performance Characteristics
Lot number
Detection Limits Limit of Quantification is defined as: The lowest actual amount of an analyte that can be reliably detected and at which the total error meets the requirements for accuracy. Gentian Cystatin C Immunoassay has a Limit of Quantification of 0.24 mg/L on the BS3801 analyser.
Temperature limitations In Vitro Diagnostic Medical Device Expiration date
Precision The Gentian Cystatin C Immunoassay was used in a 5-days precision study designed in accordance with CLSI protocol EP5A. 3 human serum pools and 2 control levels were measured on the BS3801 analyser. Sample Serum pool
Consult Instructions for Use Manufacturer Catalogue Number
Mean value (mg/L)
Within- Run CV (%)
Total CV (%)
Low
0.84
0.54
4.83
High
4.34
0.4
6.21
References
Medium
2.42
0.22
8.79
Low Control
0.87
0.97
5.29
High Control
3.19
0.24
3.73
[1] Nitsch D. et al: The Uppsala Family Stud. Am J Kidney Dis. 2011;57(6):863-872 [2] Flodin M et al: Scand J Clin Lab Invest 2007;67:560-567 [3] Shlipak M.G, et al: Clinical Chemistry 57: 737-745, 2011 [4] Sonntag O, Scholer A: Ann Clin BIochem 2001; 38:376-85. [5] CLSI; Document EP7-A; Interference Testing in Clinical Chem.; Approved Guideline [6] Larsson A et al: Poultry Science 1993;72:1807-1812
Linearity Gentian Cystatin C Immunoassay on BS3801 is linear in the range of 0.49 – 7.38 mg/L. Concentrations outside this range have not been tested. Hook Effect For Gentian Cystatin C assay there is no hook effect observed in concentration of cystatin C of less than 29.8 mg/L.
Manufacturer: Gentian AS, PO BOX 733, N-1509 Moss, Norway
Analytical Recovery
TEL: +47 99 33 99 05 FAX: +47 69 24 09 62
For the Gentian Cystatin C Immunoassay on BS3801 a recovery of 99-101% can be expected.
http://www.gentian.no
Interference No interference is detected with Haemoglobin (6 g/L), Intralipid (10 g/L) or Bilirubin (400 mg/L) on BS3801. There is no interference observed with the drugs tested on recommendation from Sonntag and Scholer [4]. The interference study was designed in accordance with the protocol EP7-A from
1 2
A registered trademark of Mindray Medical International A registered trademark of Beckman Coulter
Application Note for Gentian Cystatin C Immunoassay on BS3801, Mindray1
v01-December 2012
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Instrument Settings for Gentian Cystatin C Immunoassay on BS3801, Mindray1 Using Calibrator (REF1012)
For in vitro diagnostic use only © v01en – December 2012
Parameters: Test Information Test * No. * Std No. Full name: * Reaction parameters Reac. type Endpoint Pri. wave 546 Sec. wave Absorbance 0 0 Incre. test Decre. test
Reagent volume R1 230 R2 40
Direction Rgt. blank Reac. time Lin. range Line. Limit: Substrate Limit:
Increase 37 38 59 60 0.4 8
Sample volume Disp. Standard 3.5 Increased Decreased Result setup Decimal 0.01 Unit Mg/L
Q1
Prozone Q2
Orig. vol.
Ratio
Slop Inter.
1.08
Q3
Q4
* User defined
Calibration Using Calibrator (REF1012):
Rule!
Spline
Sensitivity:
Name: v
Replicates:
2
Interval (days):
28
Cys C – cal 1
Conc: 8.0**
Difference Limit SD Blank Response Error Limit Determ. Coeff.
0 Dilution
Application Note for Gentian Cystatin C Immunoassay on BS3801, Mindray1
v01-December 2012
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Calibrator Dilution Setup Conc. No. 0 1 2 3 4 5
Calibrator value** x 0.0404 Calibrator value** x 0.0777 Calibrator value** x 0.145 Calibrator value** x 0.354 Calibrator value** x 0.609 Calibrator value** x 1
Dil. Sample
Diluent Vol.
3.0
190
Sample Vol. 8.0
3.0
190
16.0
3.0
130
22.0
5.0
130
35.0
6.0
100
43.8
0.0
0
3.0
** Lot dependent, See analytical value sheet enclosed the calibrator.
Application Note for Gentian Cystatin C Immunoassay on BS3801, Mindray1
v01-December 2012
