CYCLASE ACTIVATING PTH (CAP) IMMUNORADIOMETRIC (IRMA) ASSAY KIT, MODEL 3KG001

K031534 · Scantibodies Laboratory, Inc. · CEW · Jul 30, 2003 · Clinical Chemistry

Device Facts

• Record ID: K031534
• Device Name: CYCLASE ACTIVATING PTH (CAP) IMMUNORADIOMETRIC (IRMA) ASSAY KIT, MODEL 3KG001
• Applicant: Scantibodies Laboratory, Inc.
• Product Code: CEW · Clinical Chemistry
• Decision Date: Jul 30, 2003
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 862.1545
• Device Class: Class 2

Intended Use

The Cyclase Activating PTH (CAP) IRMA Assay has been designed for the quantitative determination of Cyclase activating parathyroid hormone (PTH) without cross-reaction to PTH (7-84) fragment in serum and plasma samples. The 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.

Device Story

The Parathyroid Hormone (PTH) Immunoradiometric IRMA Assay is an in vitro diagnostic test used to quantify PTH levels in human serum or plasma samples. The device utilizes an immunoradiometric assay (IRMA) principle, where specific antibodies bind to the PTH analyte, allowing for detection and measurement. The assay is performed in a laboratory setting by trained technicians. Results are provided to clinicians to aid in the differential diagnosis of calcium metabolism disorders, specifically hypercalcemia and hypocalcemia. By providing accurate PTH concentration data, the device assists healthcare providers in identifying the underlying cause of abnormal calcium levels, thereby guiding appropriate clinical management and treatment strategies for patients with parathyroid-related conditions.

Clinical Evidence

No clinical data provided; bench testing only.

Technological Characteristics

Immunoradiometric assay (IRMA) using polystyrene beads coated with goat anti-PTH (39-84) and 125I-labeled goat anti-PTH tracer. Quantitative measurement range 1.0–2300 pg/mL. Requires gamma counter for detection. Reagents provided in lyophilized form. Standardized via NCCLS C28-A guidelines.

Indications for Use

Indicated for quantitative determination of cyclase activating PTH in serum and plasma to aid differential diagnosis of hypercalcemia and hypocalcemia related to calcium metabolism disorders.

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.

Submission Summary (Full Text)

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

A. 510(k) Number:
k031534

B. Analyte:
Parathyroid Hormone

C. Type of Test:
Quantitative

D. Applicant:
SCANTIBODIES Laboratory, Inc.

E. Proprietary and Established Names:
Cyclase Activating PTH (CAP) IRMA Assay

F. Regulatory Information:
1. Regulation section:
21 CFR 862.1545
2. Classification:
Class II
3. Product Code:
CEW
4. Panel:
75 (clinical chemistry and clinical toxicology)

G. Intended Use:
1. Indication(s) for use:
The Cyclase Activating PTH (CAP) IRMA Assay has been designed for the quantitative determination of Cyclase activating parathyroid hormone (PTH) without cross-reaction to PTH (7-84) fragment in serum and plasma samples. The 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.
2. Special condition for use statement(s):
NA
3. Special instrument Requirements:
Gamma counter calibrated to detect $^{125}\mathrm{I}$

H. Device Description:
The in vitro diagnostic reagent kit contains sufficient reagents for 100 single determinations. The reagents consist of the following: 7 vials of lyophilized human serum calibrator materials, 2 vials of lyophilized human serum control materials, 2 bottles of 125I tracer (goat anti-PTH), 100 polystyrene beads coated with goat anti-PTH (39-84) and one bottle of $30~\mathrm{mL}$ of phosphate buffered saline wash concentration.

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# I. Substantial Equivalence Information:

1. Predicate device name(s):
Scantibodies Laboratory Inc. Whole PTH (1-84) Specific Immunoradiometric Assay
2. Predicate K number(s):
k001411
3. Comparison with predicate:

| Item | Device | Predicate |
| --- | --- | --- |
| Intended use | For the quantitative determination of cyclase activating parathyroid hormone (PTH) without cross-reaction to PTH (7-84) fragment in EDTA plasma and serum samples | For the quantitative determination of human whole parathyroid hormone PTH (1-84) without cross-reaction to PTH (7-84) fragment in EDTA plasma samples |
| Principle of the method | Immunoradiometric (IRMA) with coated bead technology | Same |
| Measuring range | 1.0 – 2300 pg/mL | Same |
| QC and calibrator materials | 2 lyophilized QC materials and 7 lyophilized calibrators provided with assay kit | Same |
| Sample type | EDTA plasma and serum | EDTA plasma |
| Labeled polyclonal PTH antibodies directed against | PTH (1-12) and C-terminal PTH | N-terminal and C-terminal PTH |

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

NCCLS C28-A guideline

# K. Test Principle:

Immunoradiometric (IRMA) using coated bead technology

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

1. Analytical performance:

a. Precision/Reproducibility:

The inter-assay imprecision was evaluated by assaying two samples in duplicate for 20 days, using 3 kits in 20 separate assays. The inter-assay imprecision as measured by $\% \mathrm{CV}$ for sample means 16.55, 20.15, 26.96, 218.3, 219.0 and $302.1~\mathrm{pg / mL}$ were 4.15, 4.69, 4.0, 3.44, 3.71 and $2.21\% \mathrm{CV}$, respectively.

The intra-assay imprecision was evaluated by performing 20 replicates on two samples, using 3 kits. The intra-assay imprecision as measured by $\% \mathrm{CV}$ s for sample means 25.64, 24.55, 25.88, 269.88, 264.07, and $304.54~\mathrm{pg / mL}$ were 4.49, 2.36, 3.47, 2.52, 2.19, 2.34 $\% \mathrm{CV}$, respectively.

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b. Linearity/assay reportable range:
Three samples with high PTH values, 290.28, 551.44 and 670.58 pg/mL were diluted 1:2, 1:4 and 1:8 with low PTH samples. The resulting recovery values ranged from 87.8% to 96.7%.

c. Traceability (controls, calibrators, or method):

d. Detection limit:
The detection limit of the assay is defined as the lowest measurable value distinguishable from zero. The sensitivity was determined by assaying the zero calibrator 20 times in the same assay. The detection limit is approximately 1.0 pg/mL at 2 standard deviations above the PTH zero calibrator utilizing tracer less than 1 week from manufacturing.

e. Analytical specificity:
Synthetic PTH peptide (7-84) was serially diluted with the zero calibrator and assayed. The measured PTH concentration was undetectable for PTH (7-84) concentrations of 2500, 5000, 10,000, and 20,000 pg/mL.
Samples containing 100 and 200 mg/dL triglyceride, 7.5 and 15 mg/dL hemoglobin and 3.75, 7.5 and 15 mg/dL of bilirubin did not exhibit any effect on the assay as defined by recovery ranging from 96.2% to 108.6%.

f. Assay cut-off:
NA

2. Comparison studies:

a. Method comparison with predicate device:
A study analyzing 250 plasma samples, ranging in concentration from 7.2 – 1088 pg/mL, with this device (Y) and the predicate device (X) was performed. A linear regression equation of Y = 0.946X + 2.46 pg/mL, r = 0.996 was obtained.

b. Matrix comparison:
A study using 120 paired serum and plasma samples was performed. The resulting regression equation was Y (serum) = 0.94X (plasma) + 1.57 pg/mL, r = 0.971.

3. Clinical studies:

a. Clinical sensitivity:
NA

b. Clinical specificity:
NA

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

4. Clinical cut-off:
NA

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5. Expected values/Reference range:
Serum and plasma samples from 120 subjects were assayed (N=240) following the NCCLS C28-A guideline. The 95% reference interval for serum and plasma is 11-52 pg/mL.

M. Conclusion:
Based upon the information provided for the file, I recommend a determination of substantial equivalence for Cyclase Activating PTH (CAP) IRMA Assay to the predicate device regulated by 21CFR 862.1545.