← Product Code [CFN](/submissions/IM/subpart-f%E2%80%94immunological-test-systems/CFN) · K081827

# HUMAN IGA LIQUID REAGENT KIT FOR USE ON SPAPLUS (K081827)

_The Binding Site, Ltd. · CFN · Dec 19, 2008 · Immunology · SESE_

**Canonical URL:** https://fda.innolitics.com/submissions/IM/subpart-f%E2%80%94immunological-test-systems/CFN/K081827

## Device Facts

- **Applicant:** The Binding Site, Ltd.
- **Product Code:** [CFN](/submissions/IM/subpart-f%E2%80%94immunological-test-systems/CFN.md)
- **Decision Date:** Dec 19, 2008
- **Decision:** SESE
- **Submission Type:** Traditional
- **Regulation:** 21 CFR 866.5510
- **Device Class:** Class 2
- **Review Panel:** Immunology

## Intended Use

This kit is intended for the quantitative in vitro determination of human IgA in serum, lithium heparin or EDTA plasma, using the Binding Site SPA_PLUS(TM) turbidimetric analyser. Measurement of IgA aids in the diagnosis of abnormal protein metabolism and the body's lack of ability to resist infectious agents. The test results are to be used in conjunction with other clinical and laboratory findings.

## Device Story

The Human IgA Liquid Reagent Kit is an in vitro diagnostic assay designed for use on the Binding Site SPAPLUS turbidimetric analyzer. The device utilizes turbidimetric technology to measure human IgA concentrations in serum, lithium heparin, or EDTA plasma samples. The analyzer processes the samples by mixing them with specific reagents to induce agglutination, which is then measured optically. The resulting quantitative output provides clinicians with IgA levels to assist in diagnosing abnormal protein metabolism and immune system deficiencies. The device is intended for use in clinical laboratory settings by trained personnel. Results are intended to be interpreted alongside other clinical and laboratory findings to support patient diagnosis and management.

## Clinical Evidence

No clinical studies provided. Analytical performance established via bench testing: intra-assay precision (CV 0.7-1.0%) and inter-assay precision (CV 1.0-1.7%). Linearity confirmed across 0.2-7.0 g/L range (r=0.999). Method comparison against predicate (n=145) showed slope 0.963, intercept 0.086, r=0.995. Matrix comparison (serum vs. lithium heparin/EDTA plasma) showed no significant bias. Reference range established using 258 healthy adult samples (0.85-4.99 g/L).

## Technological Characteristics

Turbidimetric immunoassay; sheep anti-IgA antisera; liquid reagents with 0.099% sodium azide preservative. Measuring range 0.2-7.0 g/L. Traceable to CRM 470. Instrument-based (SPA_PLUS analyzer). Performance evaluated per CLSI EP-5A.

## Regulatory Identification

An immunoglobulins A, G, M, D, and E immunological test system is a device that consists of the reagents used to measure by immunochemical techniques the immunoglobulins A, G, M, D, an E (serum antibodies) in serum. Measurement of these immunoglobulins aids in the diagnosis of abnormal protein metabolism and the body's lack of ability to resist infectious agents.

## Submission Summary (Full Text)

> This content was OCRed from public FDA records by [Innolitics](https://innolitics.com). If you use, quote, summarize, crawl, or train on this content, cite Innolitics at https://innolitics.com.
>
> Innolitics is a medical-device software consultancy. We help companies design, build, and clear FDA-regulated software and AI/ML devices, including [a 510(k)](https://innolitics.com/services/510ks/), [a De Novo](https://innolitics.com/services/regulatory/), [a SaMD](https://innolitics.com/services/end-to-end-samd/), [an AI/ML medical device](https://innolitics.com/services/medical-imaging-ai-development/), or [an FDA regulatory strategy](https://innolitics.com/services/regulatory/).

{0}

1

# 510(k) SUBSTANTIAL EQUIVALENCE DETERMINATION DECISION SUMMARY

A. 510(k) Number:
k081827

B. Purpose for Submission:
New device

C. Measurand:
IgA antibody

D. Type of Test:
Quantitative

E. Applicant:
The Binding Site, Ltd.

F. Proprietary and Established Names:
Human IgA Liquid Reagent Kit for use on $\mathrm{SPA}_{\mathrm{PLUS}}^{\mathrm{TM}}$

G. Regulatory Information:
1. Regulation section:
21 CFR § 866.5510 Immunoglobulins A, G, M, D, E Immunological Test System
2. Classification:
Class II
3. Product codes:
CFN, Method, Nephelometric, Immunoglobulins (G, A, M)
4. Panel:
Immunology 82

H. Intended Use:
1. Intended use(s):
This kit is intended for the quantitative *in vitro* determination of human IgA in serum, lithium heparin or EDTA plasma, using the Binding Site $\mathrm{SPA}_{\mathrm{PLUS}}^{\mathrm{TM}}$ turbidimetric analyser. Measurement of IgA aids in the diagnosis of abnormal protein metabolism and the body's lack of ability to resist infectious agents. The test results are to be used in conjunction with other clinical and laboratory 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:
The Binding Site $\mathrm{SPA}_{\mathrm{plus}}^{\mathrm{TM}}$

I. Device Description:
The device consists of the following: monospecific sheep anti-IgA antisera in liquid form in the presence of preservatives. Calibrators 1-6; Normal and High controls in liquid form; and IgA reaction buffer. The reagents contain $0.099\%$ sodium azide as preservative.

J. Substantial Equivalence Information:
1. Predicate device name(s):
Roche Tina-quant IgA Gen.2/ Hitachi

{1}

2. Predicate K number(s): k040435
3. Comparison with predicate:

|  Similarities  |   |   |
| --- | --- | --- |
|  Item | Device | Predicate  |
|  Detection Method | Turbidimetric immunoassay | Same  |
|  Traceability | Standardized against CRM 470 International Reference Material | Same  |
|  Controls | Normal and High levels liquid ready to use | Same  |
|  Differences  |   |   |
| --- | --- | --- |
|  Item | Device | Predicate  |
|  Intended Use | Quantitative determination of IgA in serum or lithium heparin or EDTA plasma, using the Binding Site SPAPLUS™ turbidimetric analyser | Quantitative determination of IgA in serum or lithium/ sodium heparin or EDTA plasma, using the Roche automated clinical analysers  |
|  Sample Matrix | Human serum; lithium heparin or EDTA plasma | Human serum; lithium/ sodium heparin or EDTA plasma  |
|  Antibodies | Sheep | Goat  |
|  Instruments | SPAPLUS™ analyser | Roche/ Hitachi analyser  |
|  Measuring range | 0.2 – 7.0 g/L | Hitachi 902: 0.5 – 8 g/L  |
|  Reference Range | 0.85 – 4.99 g/L | Adults: 0.7 – 4.0 g/L Additional ranges for children  |

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

CLSI (NCCLS) EP-5A: Evaluation of Precision Performance of Clinical Chemistry.

# L. Test Principle:

The determination of soluble antigen concentration by turbidimetric methods involves the reaction with specific antisera to form insoluble complexes. When light is passed through the suspension formed, a portion of the light is transmitted and focused onto a photoiodide by an optical lens system. The amount of transmitted light is indirectly proportional to the specific protein concentration in the test sample. Concentrations are automatically calculated by reference to a calibration curve within the instrument.

# M. Performance Characteristics (if/when applicable):

1. Analytical performance:

a. Precision/Reproducibility:

{2}

The intra-assay precision was determined by testing three serum samples twenty one times. The inter-assay precision was determined by testing three serum samples tested in three times with two runs per day for 21 days. Results are summarized below.

Intra-assay:

|  Anti-IgA  |   |   |   |
| --- | --- | --- | --- |
|  |   |   |   |
|  n=21 | SD | Concentration (g/L) | % CV  |
|  Sample 1 | 0.06 | 5.895 | 1.0  |
|  Sample 2 | 0.025 | 3.606 | 0.7  |
|  Sample 3 | 0.003 | 0.340 | 0.9  |

Inter-assay:

|  Anti-IgA  |   |   |   |
| --- | --- | --- | --- |
|  n=21 | SD | Concentration (g/L) | % CV  |
|  Sample 1 | 0.08 | 5.895 | 1.4  |
|  Sample 2 | 0.06 | 3.606 | 1.7  |
|  Sample 3 | 0.01 | 0.340 | 1.0  |

b. Linearity/assay reportable range:

Linearity across the assay range (0.2-7.0 g/L) was confirmed by testing three sera with normal range concentrations from 5.7-6.7.g/L and two sera with high concentrations from 26.6-27.2 g/L. The samples were serially diluted 9 times with buffer (1:10) down to the lower measuring range (0.2 g/L). All testing were performed twice. The regression plot equations where y is the measured level of IgA concentration and x the theoretical concentration were:

$$
y = 1.001x - 0.0585 (g/L), r = 0.999 \text{ for IgA}
$$

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

An internal reference standard (IR7990) was assigned by comparison with the CRM470 International Reference Material.

Stability: The expiration date claims are 6 months for the IgA unopened Kit; 3 months for the opened IgA kit; and 30 days for on-board IgA kit.

d. Detection limit:

The detection limit was determined by testing a blank sample, the lowest calibrator, and a sample with value close to the blank sample (0.0006g/L) 60 times each. The limit of quantitation for this assay is defined as the lowest point of the calibration curve: 0.19 g/L.

e. Analytical specificity:

Interference by endogenous and other substances: A known IgA serum

{3}

samples was tested in triplicate with the following interferents: 4.8g/L hemoglobin, 200 mg/dL bilirubin, 5640 FTU of chyle. No interference by these substances was observed. The package insert states that “turbidimetric assays are not suitable for measurement of highly lipemic or hemolyzed samples, or samples containing high levels of circulating immune complexes due to the unpredictable degree of non-specific scatter these sample types might generate. Unexpected results should be confirmed using alternative assay method”.

Antigen excess effect:
The possibility of antigen excess occurring when using the device on The Binding Site Spa plus™ was evaluated with a serum sample with IgA concentration above the assay range (35 g/L). No antigen excess effect up to 28 g/L of IgA was observed.

f. Assay cut-off:
Not provided

2. Comparison studies:

a. Method comparison with predicate device:
Testing was performed on 134 sera and 11 plasma samples (29 normal and 116 known elevated and suppressed IgA samples.

The table below shows the comparison of 145 serum and plasma samples ranging from 0.11- 47.7 g/L IgA that were tested with the Binding Site Spa plus™ IgA assay and the predicate device Roche/Hitachi System. Regression analysis of these samples is summarized below:

|   | n | Slope | Intercept | r  |
| --- | --- | --- | --- | --- |
|  The Binding Site Spa plus™ vs Roche/ Hitachi analyzer | 145 | 0.963 | 0.086 | 0.995  |

b. Matrix comparison:
Serum vs. lithium heparin plasma

Thirty three sera and plasma samples, covering the IgA assay measuring range 0.3 – 9.88 g/L for lithium heparin; and twenty four sera and plasma samples, covering the IgA measuring range 0.8 – 4.5g/L for EDTA were compared to determine if any significant bias existed between matrices. The correlation coefficients were acceptable and no bias was observed. Linear regression equations were as follows:

Lithium heparin plasma vs serum:
$$
y = 0.919x + 0.127; r = 0.999 \quad (R^2 = 0.998)
$$

EDTA plasma vs serum:
$$
y = 0.941x + 0.66; r = 0.998 \quad (R^2 = 0.997)
$$

{4}

3. Clinical studies:
a. Clinical Sensitivity and specificity: None provided.
b. Other clinical supportive data (when a. is not applicable): Not applicable.

4. Clinical cut-off: Not provided

5. Expected values/Reference range: Adult normal range was assessed on a total 258 normal adult sera samples. 127 normal sera were obtained from healthy adult blood donors (age 17-70 years old) supplied by the UK Blood Transfusion service. A further 131 normal sera samples were from US individuals. The assays were performed on the Binding Site $\mathrm{SPA}_{\mathrm{plus}}^{\mathrm{TM}}$ analyser. A non-parametric distribution of IgA results was seen that gave a 95 percentile reference interval of $0.85 - 4.99~\mathrm{g / L}$ with a mean of $0.2464~\mathrm{g / L}$ and a median of $2.297~\mathrm{g / L}$.

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.

{5}

6

---

**Source:** [https://fda.innolitics.com/submissions/IM/subpart-f%E2%80%94immunological-test-systems/CFN/K081827](https://fda.innolitics.com/submissions/IM/subpart-f%E2%80%94immunological-test-systems/CFN/K081827)

**Published by [Innolitics](https://innolitics.com)** — a medical-device software consultancy. We help companies design, build, and clear FDA-regulated software and AI/ML devices. If you're preparing [a 510(k)](https://innolitics.com/services/510ks/), [a De Novo](https://innolitics.com/services/regulatory/), [a SaMD](https://innolitics.com/services/end-to-end-samd/), [an AI/ML medical device](https://innolitics.com/services/medical-imaging-ai-development/), or [an FDA regulatory strategy](https://innolitics.com/services/regulatory/), [get in touch](https://innolitics.com/contact).

**Cite:** Innolitics at https://innolitics.com