DIMENSION VISTA VITAMIN B12 AND FOLATE FLEX REAGENT CARTRIDGES AND LOCI 4 CALIBRATOR

K071224 · Dade Behring, Inc. · CDD · Nov 13, 2007 · Clinical Chemistry

Device Facts

• Record ID: K071224
• Device Name: DIMENSION VISTA VITAMIN B12 AND FOLATE FLEX REAGENT CARTRIDGES AND LOCI 4 CALIBRATOR
• Applicant: Dade Behring, Inc.
• Product Code: CDD · Clinical Chemistry
• Decision Date: Nov 13, 2007
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 862.1810
• Device Class: Class 2

Indications for Use

The B12 Flex® reagent cartridge is an in vitro diagnostic test for the quantitative measurement of Vitamin B12 in human serum and plasma on the Dimension Vista® system. Measurements obtained by this device are used in the diagnosis and treatment of gastrointestinal malabsorption. The FOL Flex® reagent cartridge is an in vitro diagnostic test for the quantitative measurement of folate in human serum and plasma on the Dimension Vista® system. Measurements obtained by this device are used in the diagnosis and treatment of megaloblastic anemia. The LOCI 4 Calibrator is an in vitro diagnostic product for the calibration of the Ferritin (FERR), Vitamin B12 (B12), and Folate (FOL) methods on the Dimension Vista® system.

Device Story

Dimension Vista B12 and Folate assays are homogeneous, competitive chemiluminescent immunoassays using LOCI technology. Input: human serum or plasma samples. Process: samples undergo pretreatment; binding proteins and Chemibeads (coated with analyte derivative and chemiluminescent dye) are added; Sensibeads (coated with streptavidin and photosensitizer dye) are added to form bead-pair immunocomplexes. Illumination at 680nm triggers singlet oxygen diffusion from Sensibeads to Chemibeads, inducing chemiluminescence measured at 612nm. Output: chemiluminescent signal inversely proportional to analyte concentration. Used in clinical laboratories on the Dimension Vista system. Results assist clinicians in diagnosing and managing anemias related to B12 or folate deficiency.

Clinical Evidence

Bench testing only. Split-sample method comparison performed against predicate ADVIA Centaur assays using clinical patient samples. B12 (n=124): slope 0.93, intercept -14.4 pg/mL, r=0.98. FOL (n=110): slope 1.02, intercept -0.07 ng/mL, r=0.96.

Technological Characteristics

Homogeneous competitive chemiluminescent immunoassay (LOCI technology). Reagents: synthetic chemibeads (coated with analyte derivative/chemiluminescent dye) and sensibeads (streptavidin-coated/photosensitive dye). Energy source: 680 nm light excitation. Detection: 612 nm chemiluminescence. Matrix: bovine serum albumin (calibrator). Automated system integration.

Indications for Use

Indicated for quantitative measurement of Vitamin B12 in human serum/plasma to diagnose/treat gastrointestinal malabsorption, and folate in human serum/plasma to diagnose/treat megaloblastic anemia. Used on Dimension Vista system.

Regulatory Classification

Identification

A vitamin B12 test system is a device intended to measure vitamin B12 in serum, plasma, and urine. Measurements obtained by this device are used in the diagnosis and treatment of anemias of gastrointestinal malabsorption.

Predicate Devices

• VB12 for the ADVIA Centaur® System (K041133)
• FOL for the ADVIA Centaur® system (K010050)
• FERR Calibrator for the Dimension system (K983548)

Submission Summary (Full Text)

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510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION
DECISION SUMMARY
ASSAY ONLY TEMPLATE

A. 510(k) Number:
k071224

B. Purpose for Submission:
New device

C. Measurand:
Vitamin B12, Folate

D. Type of Test:
Quantitative

E. Applicant:
Dade Behring

F. Proprietary and Established Names:
Dimension Vista® Vitamin B12 Flex® reagent cartridge (B12)
Dimension Vista® Folate Flex® reagent cartridge (FOL)
Dimension Vista® LOCI 4 Calibrator

G. Regulatory Information:
1. Regulation section:
21 CFR §862.1810, Vitamin B12 test system
21 CFR §862.1295, Folic acid test system
21 CFR §862.1150, Calibrator
2. Classification:
Class II
3. Product code:
CDD, CGN and JIX, respectively

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4. Panel:
75, Clinical Chemistry

H. Intended Use:

1. Intended use(s):
See indications for use below

2. Indication(s) for use:
Dimension Vista® Vitamin B12 Flex® reagent cartridge (B12)

The B12 Flex® reagent cartridge is an in vitro diagnostic test for the quantitative measurement of Vitamin B12 in human serum and plasma on the Dimension Vista® system. Measurements obtained by this device are used in the diagnosis and treatment of anemias of gastrointestinal malabsorption.

Dimension Vista® Folate Flex® reagent cartridge (FOL)

The FOL Flex® reagent cartridge is an in vitro diagnostic test for the quantitative measurement of folate in human serum and plasma on the Dimension Vista® system. Measurements obtained by this device are used in the diagnosis and treatment of megaloblastic anemia.

Dimension Vista® LOCI 4 Calibrator

The LOCI 4 Calibrator is an in vitro diagnostic product for the calibration of Ferritin (FERR), Vitamin B12 (B12) and Folate (FOL) methods on the Dimension Vista® system.

3. Special conditions for use statement(s):
For Prescription use only

4. Special instrument requirements:
Dade Behring Dimension Vista® system

I. Device Description:

The Dimension Vista™ Vitamine B12 Flex® reagent cartridge (B12) consists of prepackaged, liquid reagents in a plastic twelve well cartridge. Each well contains the following reagent: wells 1-2 B12-Chemibeads, wells 3-4 NaOH and KCN, wells 7-8 Streptavidin Sensibeads, wells 9-10 Discyanocobinamide and wells 11-12

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Biotinylated IF.

The Dimension Vista™ Folate Flex® reagent cartridge (FOL) consists of prepackaged, liquid and tablet reagents in a plastic twelve well cartridge. Each well contains the following reagent: wells 1-2 Ascorbic Acid tablet, wells 3-4 Sodium Hydroxide, wells 5-6 Dithiothreitol (DTT) tablet, wells 7-8 Folate Binding Protein and Biotinylated antibody (mouse monoclonal), wells 9-10 Folate Chemibeads and wells 11-12 Streptavidin Sensibeads.

The Dimension Vista™ LOCI 4 Calibrator is a multi-analyte liquid product containing Ferritin (cleared k070552), from human liver, Vitamin B12 and Folate in bovine serum albumin. The kit consists of ten vials, two each of five levels containing 2.5 mL per vial for level A, 1.5 mL per vial for level B, 1.0 mL per vial for levels C and D and 2.0 mL per vial for level E.

All human source material was tested by FDA-approved methods for HIV-1/2, HBsAg, and HCV and found to be negative.

## J. Substantial Equivalence Information:

1. Predicate device name(s):

Elecsys Vitamin B12 Test System, Roche Diagnostics
FOL for the Advia Centaur System, Bayer Healthcare
FERR Calibrator for the Dimension system, Dade Behring

2. Predicate 510(k) number(s):

k041133, k010050 and k983548, respectively

3. Comparison with predicate:

| Similarities | | |
| --- | --- | --- |
| Item | Dimension Vista B12 Flex reagent cartridge | Roche Elecsys Vitamin B12 Test System |
| Sample Type | Serum and Plasma | Serum and Plasma |
| Detection | Chemiluminescent | Chemiluminescent |
| Binding Protein | Purified porcine Intrinsic Factor | Purified porcine Intrinsic Factor |
| Differences | | |
| --- | --- | --- |
| Item | Dimension Vista B12 Flex reagent cartridge | Roche Elecsys Vitamin B12 Test System |
| Assay Range | 50-2000 pg/mL | 30-2000 pg/mL |
| Technology | Competitive format | Competitive format |

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| Differences | | |
| --- | --- | --- |
| Item | Dimension Vista B12 Flex reagent cartridge | Roche Elecsys Vitamin B12 Test System |
| | homogeneous immunoassay | heterogeneous immunoassay |
| Similarities | | |
| --- | --- | --- |
| Item | Dimension Vista FOL Flex reagent cartridge | FOL on the ADVA Centaur System |
| Technology | Competitive format immunoassay | Competitive format immunoassay |
| Detection | Chemiluminescent | Chemiluminescent |
| Differences | | |
| --- | --- | --- |
| Item | Dimension Vista FOL Flex reagent cartridge | FOL on the ADVA Centaur System |
| Asay Range | 0.5 -20 ng/mL | 0.35 – 24 ng/mL |
| Sample Size | 10 μL | 150 μL |
| Sample type | Serum and Plasma | Serum and Red Blood Cells |
| Similarities | | |
| --- | --- | --- |
| Item | Dimension Vista LOCI 4 Calibrator | Dimension Ferritin Calibrator |
| Matrix | Bovine Serum Albumin | Bovine Serum Albumin |
| Levels | 5 | 5 |
| Differences | | |
| --- | --- | --- |
| Item | Dimension Vista LOCI 4 Calibrator | Dimension Ferritin Calibrator |
| Intended Use | Calibrate Ferritin, Vitamin B12 and Folate | Calibrate Ferritin |
| Form | Liquid stored at 10-20 °C | Liquid stored at 2-8 °C |

# K. Standard/Guidance Document Referenced (if applicable):

CLSI EP5-A2: Evaluation of Precision Performance of Clinical Chemistry Devices; Approved Guideline

CLSI EP7-A2; Interference Testing in Clinical Chemistry; Proposed Guideline

CLSI EP6-A; Evaluation of the Linearity of Quantitative Analytical Methods

CLSI EP9-A2; Method Comparison and Bias Estimation Using Patient Samples; Approved Guideline

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L. Test Principle:

The Dimension Vista Vitamin B12 and Folate Flex assays are homogeneous, competitive chemiluminescent immunoassays based on LOCI technology. The LOCI reagents include two synthetic bead reagents and binding proteins. The first bead reagent (Chemibeads) is coated with a B12 derivative for the B12 assay and folic acid derivative for the Folate assay and a chemiluminescent dye. The second bead reagent (Sensibeads) is coated with streptavidin and contains photosensitizer dye. Samples undergo a pretreatment step. After the sample pretreatment, the binding protein and Chemibeads is added to the sample an incubated. Sensibeads are added and bind to the biotin to form bead-pair immunocomplexes. Illumination of the complex at 680nm generates singlet oxygen from the Sensibeads which diffuses to the Chemibeads and triggers a chemiluminescent reaction. The resulting chemiluminescent signal is measured at 612nm and is an inverse function of the concentration the analyte in the sample.

M. Performance Characteristics (if/when applicable):

1. Analytical performance:

a. Precision/Reproducibility:

Repeatability testing was done in accordance with CLSI Approved Guideline for Evaluation of Precision Performance of Clinical Devices: EP5-A2. Specimens at each level were analyzed in duplicate, twice a day, for 20 days. The repeatability and within-lab standard deviations (SD) and percent coefficient of variation (%CV) were calculated by the analysis of variance method. The data are summarized below.

B12
| Material | Mean pg/mL | Repeatability SD(%CV) | Within-Lab SD(%CV) |
| --- | --- | --- | --- |
| MAS Moni-Trol Level 1 | 219 | 11.2(5.1) | 13.7(6.3) |
| MAS Moni-Trol Level 2 | 541 | 15.5(2.9) | 20.1(3.7) |
| MAS Moni-Trol Level 3 | 862 | 10.8(1.3) | 17.0(2.0) |
| Serum Pool 1 | 196 | 11.3(5.8) | 13.9(7.1) |
| Serum Pool 2 | 1606 | 15.7(1.0) | 24.7(1.5) |
| Plasma Pool 1 | 278 | 11.7(4.2) | 15.6(5.6) |

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Folate

| Material | Mean ng/mL | Repeatability SD(%CV) | Within-Lab SD(%CV) |
| --- | --- | --- | --- |
| Bio-Rad Level 1 | 1.9 | 0.11(5.8) | 0.16(8.4) |
| Bio-Rad Level 2 | 4.5 | 0.18(3.9) | 0.22(5.0) |
| Bio-Rad Level 3 | 6.0 | 0.26(4.4) | 0.35(5.8) |
| Serum Pool 1 | 2.9 | 0.18(6.0) | 0.21(7.2) |
| Serum Pool 2 | 17.0 | 0.74(4.4) | 0.87(5.1) |

b. Linearity/assay reportable range:

The reportable range of 50-2000 pg/mL for B12 and 0.5-20 ng/mL for Folate is based on linearity, detection limit and method comparison.

Linearity across the assay range was confirmed by testing serum samples with high concentrations of B12 and Folate. These samples were serially diluted with the zero calibrator down to the lower measuring range (2183 to 0 pg/mL B12 and 24.4 to 0 Folate) in 9 points. Each dilution was tested in replicates of five.

The linear regression was calculated.

| | Slope | Intercept | Correlation Coefficient |
| --- | --- | --- | --- |
| B12 | 0.988 | 5.8 | 0.998 |
| FOL | 0.99 | 0.23 | 0.994 |

Recovery

B12

Two serum samples and one plasma sample with baseline values of B12 ranging from 217-276 were spiked with known amounts of USP B12 and samples were assayed. The percent recovery was calculated. The mean recovery was 96.5%.

| Sample Type | Baseline B12 pg/mL | Spike B12 pg/mL | Expected ng/mL | Obtained ng/mL | B12 % Recovery |
| --- | --- | --- | --- | --- | --- |
| Serum | 276 | 1097 | 13763 | 1283 | 93.4 |
| Serum | 217 | 1097 | 1314 | 1264 | 96.2 |
| Plasma | 271 | 1097 | 1368 | 1365 | 99.8 |

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# Folate

Four serum and two plasma samples containing elevated and low levels of native folate were tested individually and as a 1:1 mixture. The mean recovery was 103.6% 9.

| | | | 1:1 Mixture | | |
| --- | --- | --- | --- | --- | --- |
| Sample Type | FOL ng/mL Low | FOL ng/mL High | Expected ng/mL | Obtained ng/mL | FOL % Recovery |
| Serum | 1.2 | 17.0 | 9.1 | 8.4 | 92.3 |
| Serum | 4.4 | 18.7 | 11.6 | 13.0 | 112.1 |
| Serum | 3.4 | 17.8 | 10.6 | 11.1 | 104.7 |
| Serum | 2.4 | 17.2 | 9.8 | 10.5 | 107.1 |
| Plasma | 4.1 | 10.8 | 7.5 | 8.0 | 106.7 |
| Plasma | 4.4 | 11.5 | 8.0 | 7.9 | 98.8 |

## c. Traceability, Stability, Expected values (controls, calibrators, or methods):

Anchor pools are made by adding varying known quantities of the United States Pharmacopoeia (USP) grade B12 and Folate into a B12/Folate depleted human serum matrix. The concentrations are verified by testing patient samples with values across the range of the assay.

Standard values are assigned to a master calibrator lot using USP grade B12 and Folate into a bovine serum albumin matrix. Values are then assigned to the commercial calibrator (bovine serum albumin matrix at target concentration) verses master calibrator using instruments calibrated with the master pool. Each level is tested on multiple instruments for a total of >40 measurements.

Un-open calibrators stored frozen at -20 to -10° C are stable until the stated expiration date. Real time calibrator stability is ongoing. Un-open thawed calibrators stored at 2 to 8° C are stable for 30 days. Open vial punctured stability was set at 3 days.

## d. Detection limit:

The Limit of the Blank represents the lowest concentration of analyte that can be distinguished from zero and defined as the mean value (n=20 replicates) plus two standard deviations of a zero level sample. The Limit of Blank for Dimension Vista® Vitamin B12 assay and Dimension Vista® Folate assay were determined to be 20 pg/mL and 0.5 ng/mL respectively.

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# e. Analytical specificity:

Samples containing Vitamin B12 at a concentration of $190~\mathrm{pg / mL}$ and Folate at a concentration of $2.9~\mathrm{ng / mL}$ were evaluated for interference according to CLSI EP7-A. The following substances demonstrated no significant bias (defined as $< 10\%$ difference).

| Substance Tested | Substance concentration B12/Folate | Vitamin B12 pg/mL | Folate ng/mL | Bias % |
| --- | --- | --- | --- | --- |
| Hemoglobin (hemolysate) | 100 mg/dL/ Hemoglobin | 190 | Measurements cannot be made on hemolyzed specimens | <10 |
| Bilirubin (unconjugated) | 20 mg/dL | 190 | 2.9 | <10 |
| Bilirubin (conjugated) | 20 mg/dL | 190 | 2.9 | <10 |
| Lipemia (Intralipid) | 3000 mg/dL | 190 | 2.9 | <10 |

The following substances show an interference of $&gt;10\%$ :

| Substance Tested | Substance concentration | Vitamin B12 pg/mL | Bias |
| --- | --- | --- | --- |
| Albumin | 6 g/dL | 190 | ↑ results 47.1% |
| Dextran | 40 at 6 g/dL | 190 | ↓ results -28.2% |
| Immunoglobulin G | 5 g/dL | 190 | ↓ results -14.2% |
| Uric Acid | 20 mg/dL | 190 | ↑ results 26.2% |
| Substance Tested | Substance concentration | Folate ng/mL | Bias |
| --- | --- | --- | --- |
| Albumin | 6 g/dL | 2.9 | ↓ results 38% |
| Chlorpromazine | 0.2 mg/dL | 2.9 | ↑ results 16% |
| Cimetidine | 2.0 mg/dL | 2.9 | ↑ results 47% |
| Total Protein | 12 g/dL | 2.9 | ↓ results 42% |

An extensive list of other compounds was evaluated for interference and was found to have no significant interference or cross reactivity. A list of these compounds is present in the product labeling.

# f. Assay cut-off:

Not applicable

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2. Comparison studies:

a. Method comparison with predicate device:

A split sample method comparison between the Dimension Vista B12 and Roche Elecsys Vitamin B12 test system and FOL Flex reagent cartridges and the ADVIA Centaur System FOL assay were performed following CLSI EP9-A2. The correlations are as follows:

Dimension Vista® Vitamin B12 – y = 1.037 + 16.7, r = 0.984, n = 112
Dimension Vista® Folate – y = 0.989x + 0.02, r = 0.955, n = 110

b. Matrix comparison:

A serum and plasma comparison study was conducted to substantiate the use of sodium and lithium Heparin and EDTA anticoagulant for Vitamin B12 testing. Paired samples were analyzed by the assay on the Dimension Vista® system. The correlation was as follows:

Na Heparin vs. Serum – y = 0.98x + 4.0, r = 0.98, n=69, range =105-1807
Li Heparin vs. Serum – y = 0.96x + 4.7, r = 0.98, n=69, range = 111-1895
EDTA vs. Serum – y = 0.98x + 3.1, r = 0.96, n=69, range = 134-1952

A serum and plasma comparison study was conducted to substantiate the use of sodium and lithium heparin anticoagulant for Folate testing. Paired samples were analyzed by the assay on the Dimension Vista® system. The correlation was as follows:

Na Heparin vs. Serum – y = 0.97x – 0.05, r = 0.97, n=40, range = 2.1-18.6
Li Heparin vs. Serum – y = 0.97x – 0.44, r = 0.97, n=40, range = 1.8-17.3

3. Clinical studies:

a. Clinical Sensitivity:

Not applicable

b. Clinical specificity:

Not applicable

c. Other clinical supportive data (when a. and b. are not applicable):

Not applicable

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4. Clinical cut-off:
Not applicable

5. Expected values/Reference range:
The Vitamin B12 reference range was determined from a population of 157 healthy adults (78 males and 79 females). The Folate reference range was obtained from the literature. Package insert states that each laboratory should establish its own expected ranges.

Vitamin B12 – 254-1320 pg/mL (187 - 974 pmol/L)
Folate – 3.5 – 17.5 ng/mL (7.9 – 39.6 nmol/L)

Kratz A., Lewandrowski K. B. MGH Case Records – Normal Reference Laboratory Values. N Engl J Med. 1998; 339:15:1063-1072

N. Proposed Labeling:
The labeling is sufficient and it satisfies the requirements of 21 CFR Part 809.10.

O. Conclusion:
The submitted information in this premarket notification is complete and supports a substantial equivalence decision.

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