ADVIA CENTAUR INTACT PARATHYROID HORMONE (IPTH) ASSAY

K133601 · Siemens Healthcare Diagnostics, Inc. · CEW · Feb 5, 2014 · Clinical Chemistry

Device Facts

• Record ID: K133601
• Device Name: ADVIA CENTAUR INTACT PARATHYROID HORMONE (IPTH) ASSAY
• Applicant: Siemens Healthcare Diagnostics, Inc.
• Product Code: CEW · Clinical Chemistry
• Decision Date: Feb 5, 2014
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 862.1545
• Device Class: Class 2

Indications for Use

The ADVIA Centaur iPTH assay is for in vitro diagnostic use in the quantitative determination of intact parathyroid hormone (iPTH) in EDTA plasma or serum using the ADVIA Centaur and ADVIA Centaur XP systems. This assay is intended to be used to aid in the differential diagnosis of hyperparathyroidism and hypoparathyroidism.

Device Story

The ADVIA Centaur iPTH assay is a two-site sandwich immunoassay using direct chemiluminometric technology. It utilizes a Lite Reagent containing acridinium ester-labeled polyclonal goat anti-human PTH (N-terminal 1-34) antibody and a Solid Phase Reagent containing biotinylated polyclonal goat anti-human PTH (39-84 region) antibody coupled to streptavidin-coated paramagnetic latex particles. The device is used on the ADVIA Centaur and ADVIA Centaur XP systems in clinical laboratory settings. It processes patient EDTA plasma or serum samples to provide a quantitative measurement of iPTH. Healthcare providers use these results to assist in the differential diagnosis of hyperparathyroidism and hypoparathyroidism. The modification involved the qualification of new polyclonal goat anti-human PTH antibody pools.

Clinical Evidence

No clinical data. Analytical performance established via bench testing: precision (total CV 2.8-7.7%), linearity (R=1.00, range 6.3-1900 pg/mL), and limit of quantitation (6.3 pg/mL). Method comparison with predicate (n=106 plasma, n=105 serum) showed high correlation (R=1.00). Interference testing performed for endogenous substances and biotin per CLSI EP07-A2.

Technological Characteristics

Two-site sandwich immunoassay; direct chemiluminometric technology. Reagents: acridinium ester-labeled goat anti-human PTH (N-terminal) and biotinylated goat anti-human PTH (C-terminal) on streptavidin-coated paramagnetic latex particles. Assay range: 6.3-1900 pg/mL. Sample volume: 200 µL. Analyzed on ADVIA Centaur/XP systems. Standards: CLSI EP5-A2, EP17-A2, EP6-A, C28-A3c, EP7-A2, and ISO 14971.

Indications for Use

Indicated for the quantitative determination of intact parathyroid hormone (iPTH) in EDTA plasma or serum to aid in the differential diagnosis of hyperparathyroidism and hypoparathyroidism in patients.

Regulatory Classification

Identification

A parathyroid hormone test system is a device intended to measure the levels of parathyroid hormone in serum and plasma. Measurements of parathyroid hormone levels are used in the differential diagnosis of hypercalcemia (abnormally high levels of calcium in the blood) and hypocalcemia (abnormally low levels of calcium in the blood) resulting from disorders of calcium metabolism.

Predicate Devices

• ADVIA Centaur Intact Parathyroid Hormone (iPTH) Assay (k121981)

Submission Summary (Full Text)

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

A. 510(k) Number:
k133601

B. Purpose for Submission:
Modified polyclonal antibody

C. Measurand:
Intact Parathyroid Hormone (iPTH)

D. Type of Test:
Quantitative Immunoassay

E. Applicant:
Siemens Healthcare, Inc.

F. Proprietary and Established Names:
ADVIA Centaur Intact Parathyroid Hormone (iPTH) Assay

G. Regulatory Information:

| Product Code | Classification | Regulation Section | Panel |
| --- | --- | --- | --- |
| CEW | II | 862.1545
Parathyroid
hormone test system | 75 (Chemistry) |

H. Intended Use:

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

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2. Indication(s) for use: The ADVIA Centaur Intact Parathyroid (iPTH) assay is for in vitro diagnostic use in the quantitative determination of intact parathyroid hormone (iPTH) in EDTA plasma or serum using the ADVIA Centaur and ADVIA Centaur XP systems. This assay is intended to be used to aid in the differential diagnosis of hyperparathyroidism and hypoparathyroidism.

3. Special conditions for use statement(s):

For prescription use only.

4. Special instrument requirements:

Siemens ADVIA Centaur and ADVIA Centaur XP systems.

I. Device Description:

The device consists of the following two reagents:

1. Lite Reagent 5.0 mL/ reagent pack - The Lite Reagent contains acridinium ester-labeled polyclonal goat antihuman PTH (1-34 N-terminal) antibody (~1 µg/mL) in phosphate buffered saline with goat IgG, bovine gamma globulin, bovine serum albumin, and preservatives
2. Solid Phase 20.0 mL/ reagent pack - The Solid Phase reagent contains biotinylated polyclonal goat anti-human PTH (39-84 region) antibody (~3 µg/mL) and streptavidin (~0.4 mg/mL) covalently coupled to paramagnetic latex particles in phosphate buffered saline with goat IgG, bovine gamma globulin, bovine serum albumin, and preservatives

J. Substantial Equivalence Information:

| Reagent Similarities and Differences | | |
| --- | --- | --- |
| Item | Candidate Device: ADVIA Centaur Intact Parathyroid Hormone (iPTH) | Predicate Device: ADVIA Centaur Intact Parathyroid Hormone (iPTH) k121981 |
| Intended Use/Indications for Use | The ADVIA Centaur Intact Parathyroid (iPTH) assay is for in vitro diagnostic use in the quantitative determination of intact parathyroid hormone (iPTH) in EDTA plasma or serum using the ADVIA Centaur and ADVIA Centaur XP systems. This assay is intended to be used to aid in the differential diagnosis of hyperparathyroidism and hypoparathyroidism. | Same |

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| Sample Type | EDTA Plasma, Serum | same |
| --- | --- | --- |
| Measurement | Quantitative | same |
| Operating Principle | Sandwich Immunoassay | same |
| Technology | Chemiluminescence | same |
| Detection Antibody | Goat polyclonal antibody conjugated to Acridium Ester | New goat polyclonal antibody conjugated to Acridium Ester |
| Capture Antibody | Goat polyclonal antibody conjugated to biotin directly coupled to streptavidin magnetic particles | New goat polyclonal antibody conjugated to biotin directly coupled to streptavidin magnetic particles |
| Assay Range | 6.3 – 1900 pg/mL | 5.5 – 1900 pg/mL |
| Sample Volume | 200 μL | same |
| Calibrators | Siemens iPTH Calibrators | same |
| Calibration | 2 Point | same |
| Number of calibrators | Two (2) levels | same |
| Expected Values | 13.8 – 85.0 pg/mL (plasma)
12.4 – 76.8 pg/mL (serum) | same |

K. Standard/Guidance Document Referenced (if applicable):
- CLSI Guideline EP5-A2: Evaluation of Precision Performance of Qualitative Measurement Methods
- CLSI Guideline EP17-A2: Evaluation of Detection Capability for Clinical Laboratory Measurement Procedures
- CLSI Guideline EP6-A: Evaluation of the Linearity of Qualitative Measurement Methods
- CLSI Guideline C28-A3c: Defining, Establishing, and Verifying Reference Intervals in the Clinical Laboratory; Approved Guideline
- CLSI Guideline EP7-A2: Interference Testing in Clinical Chemistry; Approved Medical devices – Application of risk management to medical devices; (ANSI/AAMI/ISO 14971:2007/(R) 2010)

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L. Test Principle:

The ADVIA Centaur Intact PTH assay is a two-site sandwich immunoassay using direct chemiluminometric technology. PTH in the sample reacts with the first antibody (in the Lite Reagent) which is a polyclonal goat anti-human PTH (N-terminal 1–34) antibody labeled with acridinium ester. This complex is then captured by the solid phase (a second antibody which is a biotinylated polyclonal goat anti-human PTH (39–84 region) antibody that is preformed to streptavidin coated paramagnetic latex particles [Solid Phase]). Unbound materials are then removed by washing. Acid Reagent and Base Reagent are then added to initiate the chemiluminescent reaction. A direct relationship exists between the amount of PTH present in the patient sample and the amount of relative light units (RLUs) detected by the system.

M. Performance Characteristics (if/when applicable):

1. Analytical performance:

a. Precision/Reproducibility:

Assay imprecision (within run and total) was performed as recommended in CLSI EP5-A2. Seven samples (4 human plasma and 3 controls) with concentrations that spanned the measuring range of the device were tested in duplicate using two runs per day for twenty days. The results are summarized below.

| Sample | Conc. (pg/mL) | Within run %CV | Total %CV |
| --- | --- | --- | --- |
| Pool 1 | 16.1 | 7.1 | 7.7 |
| Control 1 | 38.7 | 3.6 | 4.7 |
| Pool 2 | 62.8 | 2.7 | 3.7 |
| Control 2 | 185 | 2.4 | 3.2 |
| Control 3 | 663 | 2.2 | 2.8 |
| Pool 3 | 839 | 3.0 | 3.9 |
| Pool 4 | 1698 | 2.3 | 3.2 |

b. Linearity/assay reportable range:

Linearity was evaluated following the guidelines of CLSI EP06-A. High and low concentration samples were mixed to prepare samples at 12 test concentrations and tested with the device. Results are summarized below:

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| Level | Observed (pg/mL) | Expected (pg/mL) | Linear Fit (pg/mL) | Non-linearity (pg/mL) | % Non-Linearity |
| --- | --- | --- | --- | --- | --- |
| 1 | 4.4 | 4.4 | -0.6 | 5.1 | N/A |
| 2 | 16.6 | 20.2 | 14.9 | 1.7 | 10.4 |
| 3 | 59.1 | 67.5 | 61.3 | -2.1 | -3.6 |
| 4 | 117 | 131 | 123 | -6.0 | -5.1 |
| 5 | 244 | 257 | 247 | -2.5 | -1.0 |
| 6 | 513 | 509 | 495 | 18.5 | 3.6 |
| 7 | 728 | 761 | 742 | -14.6 | -2.0 |
| 8 | 1025 | 1013 | 990 | 35.8 | 3.5 |
| 9 | 1241 | 1265 | 1237 | 4.0 | 0.3 |
| 10 | 1521 | 1517 | 1485 | 36.3 | 2.4 |
| 11 | 1754 | 1769 | 1733 | 21.0 | 1.2 |
| 12 | 2021 | 2021 | 1980 | 41.4 | 2.0 |

The regression statistics for the linearity study were as follows:

$$
y = 0.98x - 4.98, R = 1.00
$$

These results demonstrate linearity across the claimed measuring range of the device (6.3 - 1900 pg/mL).

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

The ADVIA Centaur Intact PTH assay standardization is maintained with internal standards manufactured using purified human iPTH (1-84); values have been assigned to correlate to a commercially available iPTH assay.

Calibrators and controls were previously cleared in k020217

On-board stability for the ADVIA Centaur Intact PTH assay was established by real time studies on the ADVIA Centaur XP system. The stability study protocol and the acceptance criteria have been found acceptable. The on board stability of the reagent is 28 days with a calibration interval of 14 days. The ADVIA Centaur Intact PTH assay reagent is stable until the date printed on the label when stored at $2 - 8^{\circ}\mathrm{C}$ .

d. Detection limit:

The Limit of Blank (LoB), Limit of Detection (LoD), and the Limit of Quantitation (LoQ) were calculated per CLSI EP17-A2. The LoB was calculated nonparametrically. The LoQ was estimated as the dose corresponding to $20\%$ Total CV using the precision profile method. A single experimental design was used to generate the data for LoB, LoD & LoQ. Five test samples were prepared by spiking analyte into diluent and/or

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diluting plasma samples to obtain the following approximate concentrations: 1, 2, 5, 10, and $15\mathrm{pg / mL}$ . These samples were tested at $n = 6\times 2$ instruments x 5 days for a total of $n = 60$ per reagent lot (2 reagents lots were used). Results were as follows:

| LoB | LoD | LoQ |
| --- | --- | --- |
| 0.1 pg/mL | 2.7 pg/mL | 6.3 pg/mL |

# e. Analytical specificity:

# Interference

Interference testing for endogenous substances and biotin was performed following the guidelines of CLSI EP07-A2. Two patient plasma pools, with endogenous iPTH concentrations of $\sim 20~\mathrm{pg / mL}$ and $\sim 200~\mathrm{pg / mL}$ were spiked with each interferent. Neat samples and spiked samples were tested at the concentrations shown in the results table below. The sponsor defines non-significant interference as a difference of less than or equal to $10\%$ between the spiked and the control samples. Results of non-significant interference are summarized in the table below.

| Interfering Substance | Highest Concentration with non-significant interference |
| --- | --- |
| Hemoglobin | 500 mg/mL |
| Triglycerides | 3,000 mg/mL |
| Conjugated Bilirubin | 40 mg/dL |
| Unconjugated Bilirubin | 40 mg/mL |
| Biotin | 1,000 mg/dL |

# Cross Reactivity

Cross reactants were tested by spiking each compound into a sample without iPTH and a sample with endogenous iPTH concentration between 20-70 pg/mL. The compounds tested, concentrations, tested, and % cross reactivity calculated are summarized below:

| Cross-reactant | Concentration tested | % cross reactivity |
| --- | --- | --- |
| PTH (1-34) fragment | 300 | 0.1 |
| PTH (39-68) fragment | 100,000 | 0.0 |
| PTH (39-84) fragment | 100,000 | 0.0 |
| PTH (44-68) fragment | 100,000 | 0.0 |
| PTH (53-84) fragment | 100,000 | 0.0 |
| PTH (7-84) fragment | 300 | 51 |
| Calcitonin | 100,000 | 0.0 |
| Beta-cross Laps | 1,000 | 0.2 |
| Osteocalcin | 100,000 | 0.0 |

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f. Assay cut-off:

Not applicable

2. Comparison studies:

a. Method comparison with predicate device:

The modified assay was compared to the unmodified (predicate) device by evaluating 106 EDTA plasma samples and 105 serum samples with concentrations that spanned the claimed measuring range. Study was performed on the ADVIA Centaur XP system. Samples were run in singlicate and Passing & Bablok Regression analysis was performed. The results are summarized below.

| Y | N | Regression Equation | R | Sample range (pg/mL) |
| --- | --- | --- | --- | --- |
| Plasma | 106 | y=0.98x+10.6 | 1.00 | 11.8 – 1862 |
| Serum | 105 | y=1.00x+5.0 | 1.00 | 9.8 - 1868 |

b. Matrix comparison:

The sponsor claims serum and EDTA plasma as acceptable sample types. See method comparison study above.

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

4. Clinical cut-off:

Not applicable

5. Expected values/Reference range:

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The reference range previously cleared in 510(k) submission number k121981 was verified following the guidelines of CLSI C28-A3c. Forty (40) EDTA plasma and 40 serum samples obtained from apparently healthy individuals (calcium and inorganic phosphorus results within their respective reference ranges) were tested. The samples were tested using 2 reagent lots across 4 different instruments and verified that the reference range is unchanged with the modified device.

The package insert states the following for expected values:

The Expected Results (from 95% of the values) are:

For plasma: 13.8 to 85.0 pg/mL (1.46 to 9.01 pmol/L)

For serum: 12.4 to 76.8 pg/mL (1.31 to 8.14 pmol/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.

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