Performance Evaluation of the ichroma SMART Analyzer in Measuring C-reactive Protein and Procalcitonin Levels

John Hoon Rim; Hyo-Jun Ahn; Kwang Kuk Yoon; Hye Ryun Kim; Young-Ah Kim; Hwan Sub Lim; Jongha Yoo

doi:10.3343/lmo.2016.6.1.19

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Rim, Ahn, Yoon, Kim, Kim, Lim, and Yoo: Performance Evaluation of the ichroma SMART Analyzer in Measuring C-reactive Protein and Procalcitonin Levels

Original Article

Clinical Chemistry

Laboratory Medicine Online 2016; 6(1): 19-24.

Published online: 1 January 2016

DOI: https://doi.org/10.3343/lmo.2016.6.1.19

Performance Evaluation of the ichroma SMART Analyzer in Measuring C-reactive Protein and Procalcitonin Levels

John Hoon Rim, M.D.^1,^2,^*, Hyo-Jun Ahn, M.T.^1,^*, Kwang Kuk Yoon, M.T.¹, Hye Ryun Kim, Kim¹, Young-Ah Kim, M.D.¹, Hwan Sub Lim, M.D.³, Jongha Yoo, M.D.¹

¹Department of Laboratory Medicine, National Health Insurance Service Ilsan Hospital, Goyang, Korea.

²Department of Laboratory Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.

³Department of Laboratory Medicine, Catholic Kwandong University International St. Mary's Hospital, Incheon, Korea.

Corresponding author: Jongha Yoo. Department of Laboratory Medicine, National Health Insurance Service Ilsan Hospital, 100 Ilsan-ro, Ilsandong-gu, Goyang 10444, Korea. Tel: +82-31-900-0909, Fax: +82-31-900-0925, jhyooken@gmail.com

Equal contributor:

*John Hoon Rim and Hyo-Jun Ahn contributed equally to this article as the co-first authors.

Received 2 March 2015 Revised 7 June 2015 Accepted 17 June 2015

(open-access):

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Background

For monitoring infection and inflammation episodes, biomarkers of host response, such as C-reactive protein (CRP) and procalcitonin (PCT), are now being recognized as useful tools in the diagnostic process. We aimed at evaluating the analytical performance of the recently developed semi-automated ichroma SMART system (Boditech Med Inc., Korea), which allows measurements of both CRP and PCT.

Methods

We evaluated the analytical performance of the ichroma SMART system and the agreement between its results and the laboratory standards for CRP and PCT measurements. The precision and linearity as well as the method of measurement were compared to the DxC 800 (Beckman Coulter, USA) for CRP and to the VIDAS (bioMerieux SA, France) for PCT, according to corresponding CLSI guidelines. Additionally, we evaluated the carryover rates between specimens.

Results

The total precision (% CV) of the ichroma SMART system in measuring low, middle, and high level controls (level 1, 2, 3) was 6.32%, 5.75%, and 3.56% for CRP, and 8.07%, 6.24%, and 6.53% for PCT. In the linearity test, R² was 0.9997 and 0.9982 for CRP (0.1-336.8 mg/L) and PCT (0.05-60.91 ng/mL), respectively. Good correlation was observed between ichroma SMART and DxC 800 for CRP (r=0.997), and between ichroma SMART and VIDAS for PCT (r=0.992). Carry-over effect was 0.02% for CRP and 0.04% for PCT.

Conclusions

The ichroma SMART system showed an adequate performance and appeared to be a suitable clinical analyzer with a simple operating procedure for the measurement of CRP and PCT.

Keywords: C-reactive protein, Procalcitonin, ichroma SMART

Figures and Tables

Fig. 1

Linearity curves of measured value vs. expected value for CRP and PCT using ichroma SMART.

Fig. 2

Comparison of CRP values measured by the DxC 800 and ichroma SMART.

Fig. 3

Comparison of PCT values measured by the VIDAS and ichroma SMART.

Table 1

Precision of measurement of CRP and PCT by ichroma SMART

Items	Level	N	Mean	Within-run		Total
Items	Level	N	Mean	SD	CV (%)	SD	CV (%)
CRP (mg/L)	1	20	7.42	0.37	5.04	0.47	6.32
	2	20	33.34	1.84	5.53	1.92	5.75
	3	20	127.67	4.63	3.62	4.54	3.56
PCT (ng/mL)	1	20	0.51	0.03	6.18	0.04	8.07
	2	20	1.13	0.05	4.40	0.07	6.24
	3	20	11.94	0.45	3.74	0.78	6.53

Abbreviations: CRP, C-reactive protein; PCT, procalcitonin; SD, standard deviation; CV, coefficient of variation.

Table 2

Comparison of ichroma SMART with conventional analyzers at the medical decision levels by Passing-Bablok regression

Analytes	Slope (95% CI)	Intercept (95% CI)	Decision level	Acceptable performance^*	Expected value	Expected bias
CRP (mg/L)	1.067 (1.048-1.083)	0.119 (-0.772-0.585)	10	21.8%	10.79	7.9%
			40	21.8%	42.80	7.0%
			200	21.8%	213.52	6.8%
PCT (ng/mL)	0.836 (0.799-0.889)	0.052 (0.036-0.076)	0.5	6.9%	0.47	-5.9%

^*Acceptable performance criteria were adapted from reference 8 and reference 9 for CRP and PCT, respectively.

Notes

This article is available from http://www.labmedonline.org

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