TRANSFERRIN KIT FOR USE ON THE SPAPLUS

K120236 · The Binding Site Group , Ltd. · DDG · Feb 13, 2013 · Immunology

Device Facts

• Record ID: K120236
• Device Name: TRANSFERRIN KIT FOR USE ON THE SPAPLUS
• Applicant: The Binding Site Group , Ltd.
• Product Code: DDG · Immunology
• Decision Date: Feb 13, 2013
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 866.5880
• Device Class: Class 2

Indications for Use

The Binding Site Human Transferrin Kit is intended for the quantitative determination of human transferrin using the Binding Site SPAPlus™ turbidimetric analyzer in human serum. The measurement of transferrin levels aids in the diagnosis of malnutrition, acute inflammation, infection and iron deficiency anemia. This test should be used in conjunction with other laboratory and clinical findings.

Device Story

The Human Transferrin Kit is an in vitro diagnostic assay for use on the SPAPlus™ turbidimetric analyzer. It utilizes sheep anti-human transferrin antiserum to react with transferrin in human serum, forming insoluble complexes. The analyzer passes light through the sample; an optical lens system focuses transmitted light onto a photodiode. The amount of transmitted light is inversely proportional to the transferrin concentration. The instrument automatically calculates concentrations using a calibration curve. The device is intended for use in clinical laboratory settings by trained personnel. Results assist clinicians in diagnosing iron deficiency anemia, malnutrition, and inflammatory conditions. The kit includes antiserum, calibrators, controls, and reaction buffer.

Clinical Evidence

No clinical data provided. Substantial equivalence is based on bench testing and performance characteristics of the assay on the SPAPlus analyzer.

Technological Characteristics

Turbidimetric immunoassay for the quantitative determination of human transferrin. Designed for use on the SPAPlus automated analyzer. Analyzes human serum samples.

Indications for Use

Indicated for the quantitative determination of human transferrin in human serum to aid in the diagnosis of malnutrition, acute inflammation, infection, and iron deficiency anemia. For use by clinical laboratory professionals.

Regulatory Classification

Identification

A transferrin immunological test system is a device that consists of the reagents used to measure by immunochemical techniques the transferrin (an iron-binding and transporting serum protein) in serum, plasma, and other body fluids. Measurement of transferrin levels aids in the diagnosis of malnutrition, acute inflammation, infection, and red blood cell disorders, such as iron deficiency anemia.

Submission Summary (Full Text)

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510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION DECISION SUMMARY

A. 510(k) Number:
k120236

B. Purpose for Submission:
New device

C. Measurand:
Transferrin

D. Type of Test:
Quantitative Immunoturbidimetric

E. Applicant:
The Binding Site Group, Ltd.

F. Proprietary and Established Names:
Human Transferrin Kit for use on the SPAPlus™

G. Regulatory Information:
1. Regulation section:
21 CFR §866.5880 Transferrin Immunological Test System
2. Classification:
Class II
3. Product code:
DDG, Transferrin, Antigen, Antiserum, Control
4. Panel:
Immunology (82)

H. Intended Use:
1. Intended use(s):
The Binding Site Human Transferrin Kit is intended for the quantitative determination of

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human transferrin using the Binding Site SPAPlus™ turbidimetric analyzer in human serum. The measurement of transferrin levels aids in the diagnosis of malnutrition, acute inflammation, infection and iron deficiency anemia. This test should be used in conjunction with other laboratory and clinical findings.

2. Indication(s) for use:

Same as Intended Use

3. Special conditions for use statement(s):

For prescription use only

4. Special instrument requirements:

SPAPlus™ turbidimetric analyzer

I. Device Description:

The Human Transferrin Kit for use on SPAPlus™ consists of the following:

- Human transferrin antiserum: mono-specific antiserum for transferrin and supplied in stabilized liquid form containing 0.099% sodium azide, 0.1% EACA, 0.1% EDTA and 0.01% benzamidine, as preservatives.
- Calibrator and Controls: consisting of pooled human serum and supplied in stabilized liquid form containing 0.099% sodium azide, 0.1% EACA and 0.01% benzamidine, as preservatives.
- Reaction Buffer: containing 0.099% sodium azide, as preservative.

J. Substantial Equivalence Information:

1. Predicate device name (s) and 510(k) numbers:

Dade Behring N Antisera to Human Transferrin, k053075

2. Comparison with predicate:

| Similarities | | |
| --- | --- | --- |
| Item | Human Transferrin Kit for use on the SPAPlus™ (New Device) | N Antisera to Human Transferrin (Predicate) |
| Intended Use/Indication for Use | For in vitro diagnostic use in the measurement of human transferrin in serum as an aid in the diagnosis of iron deficiency anemia. | Same |
| Storage Temperature | 2 – 8°C | Same |

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| Differences | | |
| --- | --- | --- |
| Item | Human Transferrin Kit for use on the SPAPlus™ (New Device) | N Antisera to Human Transferrin (Predicate) |
| Instruments | SPAPlus™ | BN systems |
| Assay Principle | Turbidimetric | Nephelometric |
| Antibody | Sheep, anti-human transferrin | Rabbit, anti-human transferrin |
| Sample Type | Serum | Serum, heparinized or EDTA plasma |
| Measuring range | 0.14 – 5.6 mg/L | 0.35 – 5.6 mg/L |
| Open Vial Stability | Three months, 2 – 8°C | 4 weeks, 2 – 8°C |
| On Board Stability | 30 days | 5 days with 8 hours per day |

# K. Standard/Guidance Document Referenced:

CLSI EP5-A2: Evaluation of Precision Performance of Quantitative Measurement Methods; Approved Guideline - Second Edition.

CLSI EP6-A: Evaluation of the Linearity of Quantitative Measurement Procedures: a Statistical Approach; Approved Guideline.

CLSI EP17-A: Protocols for Determination of Limits of Detection and Limits of Quantitation; Approved Guideline.

CLSI C28-A3: Defining, Establishing, and Verifying Reference Intervals in the Clinical Laboratory; Approved Guideline - Third Edition

CLSI EP9-A2: Method Comparison and Bias Estimation Using Patient Samples; Approved Guideline - Second Edition.

# L. Test Principle:

Transferrin present in serum reacts with anti-transferrin specific antiserum to form insoluble complexes. When light is passed through the suspension, a portion of the light is transmitted and focused onto a photodiode by an optical lens system. The amount of transmitted light is indirectly proportional to the transferrin concentration in the test sample. Concentrations are automatically calculated by reference to a calibration curve within the instrument.

# M. Performance Characteristics:

# 1. Analytical performance:

# a. Precision/Reproducibility:

A precision study was conducted in accordance with CLSI document EP05-A2. Four serum pools (one high transferrin-spiked serum pool, two mid sample serum pools and one low sample serum pool) spanning a large portion of the measuring range $(0.14\mathrm{g / L}$ to $5.60~\mathrm{g / L})$ were used for this study. All samples were analyzed in duplicate per run, with 2 runs per day for 21 days, using 3 reagent lots and 3

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analyzers with one operator, for a total of 84 replicates per sample. The results are summarized below:

| Serum Sample | Mean Spiked Transferrin (g/L) | Within Run | | Between Run | | Between Day | | Total | |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| | | SD | %CV | SD | %CV | SD | %CV | SD | %CV |
| Low | 0.261 | 0.0036 | 1.6 | 0.0037 | 1.7 | 0.0143 | 6.5 | 0.0152 | 6.9 |
| Mid | 1.988 | 0.0280 | 1.4 | 0.0329 | 1.7 | 0.0677 | 3.5 | 0.0803 | 4.1 |
| Mid | 3.752 | 0.0690 | 1.8 | 0.0569 | 1.5 | 0.1489 | 4.0 | 0.1737 | 4.6 |
| High | 4.210 | 0.0956 | 2.2 | 0.1946 | 4.4 | 0.1027 | 2.3 | 0.2399 | 5.5 |

Lot-to-lot data:

| Sample | Mean g/L Inter-batch | Lot-to-lot | |
| --- | --- | --- | --- |
| | | SD | %CV |
| Low | 0.221 | 0.014 | 6.19 |
| Mid | 1.941 | 0.035 | 1.79 |
| Mid | 3.742 | 0.076 | 2.04 |
| High | 4.399 | 0.046 | 1.05 |

b. Linearity/assay reportable range:

A linearity study was performed following CLSI document EP-6-A, Evaluation of the Linearity of Quantitative Measurement Procedures; Approved Guideline. Serum linearity across the assay range (0.123 to $6.095\mathrm{g / L}$ ) was evaluated by testing thirteen samples with concentrations of transferrin evenly distributed throughout the assay range. The high serum pool $(6.095\mathrm{g / L})$ was established by spiking with pure transferrin. The series of thirteen serum samples were prepared by dilution of the high serum pool with the low serum pool $(0.123\mathrm{g / L})$ to give the following thirteen samples: 100, 90, 80, 70, 60, 50, 40, 30, 20, 20, 5, 2.5, 0 (g/L). Each sample was tested in triplicate. The $\%$ recovery was calculated as the difference of the expected values and the observed values. The $\%$ recovery ranged from 80 to $120\%$ . Linear regression of observed values versus expected values showed that the slope, intercept and $\mathbf{r}^2$ were 0.9791, 0.1235 (g/L) and 0.9965, respectively.

Antigen Excess

In this study a normal sample was aliquotted and then each aliquot was spiked with increasing concentrations of transferrin. All samples were run according to the product insert at standard 1/10 instrument dilution (measuring range $0.14 - 5.60\mathrm{g / L}$ ).

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At this dilution, results were observed to be outside of the measuring range. Samples were then re-diluted to a higher 1/40 dilution and re-tested. The recovery of the samples demonstrated that antigen excess is not observed at concentrations up to at least 3-fold the upper assay range, approximately 17.0 g/L.

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

**Traceability:**

The values of the calibrator and controls are established by comparison of an internal reference standard to ERM-DA470k.

**Stability:**

Real time stability studies were performed to support the following stability claims of the Transferrin Kit for use on SPAPlus™. Onboard stability of the Transferrin Antiserum and Reaction buffer is 30 days provided that the reagent carousel is maintained at 8-12°C. Shelf-life stability of the unopened Transferrin Kit stored at 2-8°C is 12 months. Shelf-life stability of the opened Human Transferrin Antiserum, Reaction Buffer, calibrators and controls can be stored up to three months after opening, provided they are capped and stored at 2-8°C. The assay can run for 35 days without recalibration.

d. Detection limit:

Testing for limit of detection (LoD) and limit of blank (LoB) was conducted in accordance with CLSI guideline EP-17A. The LoB study was carried out using instrument diluent/saline. Sixty replicates of a blank sample were run on one day using one reagent lot. The LoD study was carried out using a low level sample (non-processed serum diluted with saline to give an analyte concentration of 0.052 g/L). Sixty replicates were run on one day using one reagent lot. The LoQ was determined by assaying 40 replicates of the assay calibrator. The following results were obtained:

LoB = 0.051 g/L
LoD = 0.059 g/L
LoQ = 0.14 g/L

e. Analytical specificity:

Interference by endogenous substances were evaluated by addition of hemoglobin (5 g/L), bilirubin (200 mg/L) and chyle (1560 FTU) to test serum samples representing analyte concentrations at the lower end of the reference range (2.100 g/L), just above the upper end of the reference range (3.725 g/L), as well as a supranormal concentration (4.748 g/L), and comparing their recovery to unspiked sample. No significant interference (i.e., sample recovers within ±10% of the unspiked sample)

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was observed with the interferents tested at any of the transferrin levels tested.

f. Assay cut-off:

See Expected Value.

2. Comparison studies:

a. Method comparison with predicate device:

Performance of the Human Transferrin Kit for use on $\mathrm{SPAPlus}^{\mathrm{TM}}$ was evaluated against the predicate using a total of 57 samples, including normal samples $(n = 26)$ , as well as samples from patients with conditions such as Goodpasture's syndrome, glomerulonephritis, iron deficiency anemia and hemochromatosis $(n = 31)$ .

Results from least squares linear regression are summarized below:

| N | Range (g/L) | Slope (95% Confidence Intervals) | Intercept (95% Confidence Intervals) | r | Syx(g/L) |
| --- | --- | --- | --- | --- | --- |
| 57 | 0.140-5.74 | 0.93 (0.88-0.98) | 0.14 (-0.01-0.29) | 0.981 | 0.265 |

Results from the experiment are shown graphically below:


b. Matrix comparison:

Not Applicable

3. Clinical studies:

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a. Clinical Sensitivity:

Not applicable

b. Clinical specificity:

Not applicable

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

Not applicable

4. Clinical cut-off:

Not applicable

5. Expected values/Reference range:

The reference interval of 2.0 – 3.5 g/L was transferred from the predicate following CLSI C28-A3. The sponsor added a caution to the labeling that states, “The ranges provided have been obtained from a limited number of samples and are intended for guidance purposes only. Wherever possible it is strongly recommended that local ranges are generated.”

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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