Khalid Sherif, Sherry Bakhtiari, Ms. Muneeza Esani, M.H.A, MT(ASCP) Clinical Assistant Professor (UTMB).H.A, MT(ASCP) Clinical Assistant professor UTMBDepartment of Clinical Laboratory Science

The University of Texas Medical Branch, Galveston TX

OPTI-LION Chemistry Analyzer Validation Study

Objectives: To compare OPTI-LION Electrolyte Analyzer to VITROS 5,1 fs ChemistryAnalyzer and validate OPTI-LION for measurement of Na+, K+, and Cl-.

Design: A linearity study was performed to validate the accuracy of new method . UTMBreference ranges for Na+, K+, and Cl- were validated using non-parametric statistics. Alinear regression was used to compare OPTI-LION to VITROS.

Setting: The study was performed at UTMB CLS students’ laboratory.

Participants: Discarded patients’ serum samples drawn from the patients of UTMB JohnSealy Hospital were used.

Intervention: Patients’ samples were run within 48 hours from the initial venipuncturedraw.

Result: OPTI-LION showed linearity for all levels of standards used Na+, K+, and Cl-. Na+

revealed a slope of 0.919, a y-intercept of 6.04, and a bias of 5.16 mmol/L. K+ revealed aslope of 1.002, a y-intercept of 0.05, and bias of 0.04 mmol/L. Cl- revealed a slope of0.949, a y-intercept of 4.82, and bias of 0.40 mmol/L.

Conclusion: OPTI-LION Chemistry Analyzer is clinically useful in point-of-care location formeasurement of Na+, K+ and Cl-. However, OPTI-LION showed significantly lower valuesfor Na+. Based on the results we obtained in this study, we recommend that changes inreference range be made to (126-141) mmol/L, (3.3-5.0) mmol/L, and (96-107) mmol/Lfor Na+, K+, and Cl- respectively or appropriate factors be added to these electrolytes.

Abbreviation: Na= sodium, K= potassium, Cl- = Chloride, UTMB= University of TexasMedical Branch, CLS= Clinical Laboratory Science, R2= Correlation coefficient.

Mesh: Method comparison and Validation studies 1

Abstract

Method comparison and reference range validation are performed forevery new method that is introduced in a laboratory. The ClinicalLaboratory Improvement Act (CLIA) of 2003 requires all non-waivedlaboratory methods must be validated1

The OPTI LION Electrolyte Analyzer (OPTI Medical) is intended to be usedfor the measurement of Na+, K+, and Cl- in samples of whole blood, serum,and plasma 2.VITROS, (Ortho-Clinical Diagnostics) Chemistry Analyzer uses a slide that isa multilayered, analytical element coated on a polyester support that usesdirect potentiometer for measurement of ionic electrolyte3

The objectives of this study wereTo determine the linearity range of OPTI-LION.To compare OPTI-LION Electrolyte Analyzer with VITROS 5,1.To validate patient reference range using OPTI-LION.

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VITROS 5,1 fs Chemistry Analyzer

OPTI-LION Electrolyte Analyzer

Materials and Methods

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73 normal samples were run for Na+

25 abnormal and 48 samples were in the UTMB’snormal reference range (135 – 145 mmol/L).73 normal samples were run for K+, 24 abnormal andthe other 49 samples were in the UTMB’s normalreference range (3.5 – 5.0 mmol/L).58 normal sample Cl-, 19 of the samples wereabnormal and the other 39 samples were in theUTMB’s normal reference range (98 – 108 mmol/L).

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RNA Medical Level(Control)

Sodium (Expected)mmol/L

Sodium (Observed) mmol/L Mean Test (Observed)mmol/L

Range(mmol/L)

Mean(mmol/L)

Test 1(mmol/L)

Test 2(mmol/L)

Test 3(mmol/L)

2 102-112 102 105 103 104 104

3 129-139 134 130 131 132 131

4 152-166 159 155 154 154 154

Table 1 Linearity Studies Using RNA Medical (Bionostic, Inc.) for sodium

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Linearity for Na+ was performed by running E-LYTES cassettes and RNA Medical(standard) level 2, level 3, and level 4 in triplicate using OPTI-LION.

RNA Medical Level(Control)

Potassium(Expected)mmol/L

Potassium (Observed) mmol/L Mean Test (Observed)mmol/L

Range(mmol/L)

Mean(mmol/L)

Test 1(mmol/L)

Test 2(mmol/L)

Test 3(mmol/L)

2 78-90 84 79 83 80 81

3 92-108 100 97 95 97 96

4 118-134 126 122 120 122 121

Table 2 Linearity Studies Using RNA Medical (Bionostic, Inc.) for potassium

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Linearity for K+ was performed by running E-LYTES cassettes and RNA Medical(standard) level 2, level 3, and level 4 in triplicate using OPTI-LION.

RNA Medical Level(Control)

Chloride (Expected)mmol/L

Chloride (Observed) mmol/L Mean Test (Observed)mmol/L

Range(mmol/L)

Mean(mmol/L)

Test 1(mmol/L)

Test 2(mmol/L)

Test 3(mmol/L)

2 102-112 102 105 103 104 104

3 129-139 134 130 131 132 131

4 152-166 159 155 154 154 154

Table 3 Linearity Studies Using RNA Medical (Bionostic, Inc.) for chloride

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Linearity for Cl- was performed by running E-LYTES cassettes and RNA Medical (standard)level 2, level 3, and level 4 in triplicate using OPTI-LION.

y = 0.919x + 6.042R² = 0.842

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0

50

100

150

200

250

300

-50 0 50 100 150 200 250 300

OPTI-LION(New)mmol/L

Vitros(refernce) mmol/L

Method Comparison Vitros vs OPTI-Lion (Sodium)

Figure 1

The linear regression graph for sodium result determined by VITROS and OPTI-LION. 48 normal and 25 abnormal serum samples were used.

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y = 1.001x - 0.047R² = 0.975

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-2

0

2

4

6

8

10

12

-4 -2 0 2 4 6 8 10 12

OPTI-LION(New)mmol/L

Vitros(reference) mmol/L

Method Comparison Vitros vs OPTI-LION (Potassium)

Figure 2

The linear regression graph for potassium result determined by VITROS and OPTI-LION. 48 normal and 25 abnormal serum samples were used. 1

y = 0.949x + 4.820R² = 0.822

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0

50

100

150

200

250

-50 0 50 100 150 200 250

OPTI-LION(New)mmol/L

Vitros(reference) mmol/L

Method Comparison Vitros vs OPTI-LION (Chloride)Figure 3

The linear regression graph for chloride result determined by VITROS and OPTI-LION. 39 normal and 19 abnormal serum samples were used.

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•Only 58% of normal serum samples were within UTMB’sreference range for Na+ .•92% normal serum samples for Cl- were within UTMB’sreference range .•96% of normal serum samples for K+ were in UTMB’sreference range.•None of the electrolytes except K+ showed Gaussiandistribution.•As a result, non-parametric statistics was used to calculatethe reference range.• Na+ had a reference range of (126-141) mmol/L.• K+ had a reference range of (3.3-5.0) mmol/L.• Cl- had a reference range of (96-107) mmol/L.

(R2) was acceptable for K+ 0.976. Na+ and Cl- had relatively lower (R2) of 0.842and 0.823 respectively.The slopes of the best-fit lines for K+ and Cl- were close to 1.0Na+ had slightly lower slope. In clinical laboratory, a slope of 0.90 to 1.00 isconsidered acceptable4.The bias for K+ and Cl- were acceptable according to the CLIA’s allowable errorranges. Na+ result demonstrated higher bias than CLIA’s allowable error range5

.Total systemic error for K+ and Cl- were within CLIA’s allowable error ranges.Na+ had higher than CLIA’s allowable error rang5 .The reference range validation for K+ and Cl- were slightly lower than theUTMB. However, Na+ showed significantly lower reference range compared toUTMB’s.There might be a number of other factors that contribute to the significantlylower measurement of Na+ and relatively lower R2 values for Na+ and Cl-.Generally OPTI-LION obtained average lower results of 6 mmo/L and 4.8mmol/L for Na+ and Cl- respectively when compared to VITROS

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Sample integrity probably contributed for these discrepancies. Our serumsamples were not fresh samples directly drawn from the patients.Our samples were collected after John Sealy Hospital completed analyzingtheir patients’ samples. This likely contributed to the lower measurements bythe OPTI-LION method.The major limitations in this study were to find enough abnormal patients’samples for K+, and Cl- and budget constraints to run large patients’ samples inorder to have enough abnormal samples.Based on the result we obtained in this study, we recommend that changes inreference range be made to (126-141) mmol/L, (3.3-5.0) mmol/L, and (96-107) mmol/L for Na+, K+, and Cl- respectively or appropriate factors be addedto these electrolytes.more studies with fresh serum samples need to be performed for methodcomparison and samples need to be run simultaneously to avoid lag intransporting the samples.In conclusion, OPTI-LION showed linearity for all levels of the standards used.OPTI-LION should perform well in traditional or clinical laboratories or point-of-care settings. Overall, OPTI-LION performed well except for Na+ and it canbe helpful to be used in point-of-care locations for the measurement of Na+

K+, and Cl-

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1. Westgard J.O.PhD. Final CLIA Rule. Part V: Method Validation Process and Procedures.Tools, Technologies and Training for Healthcare Laboratories, Westgard QC Web site. http://www.westgard.com/cliafinalrule5.htm. Accessed on April24, 2003.

2. Opti Medical Systems, Inc. OPTI-LION Operator’s Manual PD7200. Roswell, GA:OPTIMedical. 2007.

3. Ortho-Clinical Diagnostics, Inc. Clinical Laboratories VITROS 5,1 FS Website.http://www.orthoclinical.com/enus/ProductInformation/ClinicalLaboratories/VITROS 51FS/Pages/Overview.aspx. Accessed on 2003.

4. Arneson, W, MS, MT(ASCP), Brickell J, EdD, MT(ASCP), eds. Clinical Chemistry aLaboratory Perspective. Philadephia, PA; F. A. Davis Company. 2007.

5. Westgard, J. CLIA Proficiency Testing criteria. Tools, Technologies and Training for Healthcare Laboratories, Westgard QC Web site. http://westgard.com/clia.htm#chem. Accessed on February 28, 1992

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We would like to appreciate people who helped us to accomplish this study• Ms. Muneeza Esani, M.H.A, MT(ASCP) Clinical Assistant professor (UTMB)

• Ms. Nancy Berry, BS, MT(ASCP) SC Medical Technologist II (UTMB)

• Ms. Camellia St. John, Med, MT(ASCP) SBB Associate professor (UTMB)

• All the staff in John Sealy Hospital’s Clinical Chemistry Laboratory(Galveston, Texas)