ANALYTICAL EVALUATION OF THE NEW RANDOM ACCESS BENCH TOP ANALYSER
RX daytona plus
Brown M., McGivern P., Campbell J., O’Neill G., FitzGerald S.P.
Randox Laboratories limited, 55 Diamond Road, Crumlin BT29 4QY, United Kingdom
Introduction
Results
The availability of fully automated clinical chemistry analysers capable of
facilitating quick and precise analysis is beneficial in the process of patient
diagnosis. This is relevant to those assays used, for example, in the diagnosis
of a cardiac event.
Sensitivity and linearity
Mean Result U/L
700
300
200
600
100
500
0
400
0
2
300
0
2
12/009/AST
Stability
900
800
800
700
700
600
600
500
Conc. U/L
500
400
Conc. U/L
900
4
6
8
10
Level
12
Level
Mean
Linear Fit to Levels 1-3
Linear Fit to Levels 2-4
300
200
200
100
100
0
0
Level 1 QC
Level 2 QC
Level 1 QC Level 3 QC
Level 2 QC Calibrator Level 4
Level 3 QC
Calibrator Level 4
0
12/010/AST
7
Precision
7
14
Day
14
Day
21
21
28
28
Specimen type
n
Mean
U/L
Within-run precision
SD
%CV
Total precision
SD
%CV
Serum Control L2
80
162
2.23
1.4
2.69
1.7
Serum Control L3
80
38
1.14
3.0
1.29
3.4
Serum Pool
80
850
4.57
0.5
11.62
1.4
Serum Pool
80
19
0.43
2.3
1.08
5.8
12/012/AST
Method Comparison
AST: RX daytona plus vs. analyser A
900
800
700
600
500
400
300
Y=1.03x + 4.64
r= 0.999
n=120
Range: 0-817 U/L
200
100
0
Conclusion
8
400
300
0
6
AST assay on RX daytona plus
Reagent on-board stability
AST assay on RX daytona plus
Reagent on-board stability
1000
1000
4
Mean
Linear Fit to Levels 1-3
Linear Fit to Levels 2-4
0
RX daytona plus (U/L)
Method comparison
A method comparison study was conducted by testing 60 serum samples in duplicate
using this assay on the RX daytona plus (Y) and on another commercially available clinical
chemistry analyser (X). Linear least squares regression was used for the correlation
calculation. The data was collected using 5 separate runs over 5 days.
400
100
The assay is applicable to the fully automated RX daytona plus analyser (RX4040). This
system requires 5.3µl of neat sample and reagent volumes of 100µl for reagent R1 and
20µl for reagent R2.The first result is generated after 14 minutes and the system includes
dedicated software for data management.
Precision
Within-run and total precision were assessed by testing serum samples at defined medical
levels, 2 replicates twice a day for 20 days. Precision estimates were completed according
to CLSI documents EP5-A2.
500
200
The indicator reaction utilizes the oxaloacetate for a kinetic determination of NADH consumption.
MDH
oxaloacetate + NADH + H+
L-malate + NAD+
Stability
On-board and calibration stabilities were tested by storing one lot of reagent uncapped
on the RX daytona plus analyser for a period of 28 days.
Mean Result U/L
800
α-oxoglutarate reacts with L-aspartate in the presence of AST to form L-glutamate plus oxaloacetate.
AST
α-oxoglutarate + L-aspartate
L-glutamate + oxaloacetate
Linearity
The linearity was determined by assessment of replicates of a 10 point linear dilution
series of an AST spiked serum sample with an upper limit of 1000U/L.
AST Linearity
600
900
The principle of the assay is as follows:
Sensitivity
The Limit of Blank was established by testing 120 replicates of a 0.9% saline solution.
Statistics detailed in C.L.S.I. guideline EP17-A ‘Protocols for Determination of Limits
of Detection and Limits of Quantitation’ were then applied to the data generated to
determine the assay Limit of Blank. Limit of Blank (LoB) is the highest measurement result
that is exceeded 5% of the time for a blank sample.
800
700
1000
For quantitative in vitro determination of aspartate aminotransferase (AST) activity in
serum and plasma, the assay kit AST was used (AS8306).
Analytical parameters
900
12/009, 011/AST
Methodology
The assay was performed following the manufacturer’s instructions.The Calibration serum
Level 3 (CAL2351) was used.
The kit, calibrators, controls, and RX daytona plus analyser were manufactured by Randox
Laboratories Limited (Crumlin, United Kingdom).
1000
AST assay on RX daytona plus
Limit of Blank (U/L) Linearity (U/L)
0.5
927
This study reports the evaluation of a newly developed fully automated bench
top system, the RX daytona plus. This is demonstrated with the evaluation of
an aspartate aminotransferase (AST) assay. Elevated levels of AST can signal
myocardial infarction.
AST Linearity
0
12/013/AST
200
400
600
Analyser A (U/L)
800
• The results from this evaluation indicate optimal analytical performance of the enzymatic IFCC assay for in vitro quantification
of AST in serum and plasma samples on the RX daytona plus analyser using liquid assay components.
• The easy to use software of this new developed analyser facilitates the input of assay parameters and testing work lists.
• Excellent agreement with other commercially available systems.
• Low minimum reaction volume of 100µl is required.
• 270 photometric tests per hour can be generated.
• Overall the system represents a useful cost-effective analytical tool for the clinical chemistry laboratory.
Randox Laboratories Limited, 55 Diamond Road, Crumlin, County Antrim, BT29 4QY, United Kingdom T +44 (0) 28 9442 2413 F +44 (0) 28 9445 2912 E [email protected] I www.randox.com
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