The AquaLite® Intact PTH Bioluminescent Immunoassay (BLA) Kit (or the AquaLite® Intact PTH assay) is intended to be used in clinical laboratories for the quantitative determination of human intact parathyroid hormone in serum mongunested, Intact PTH measurements are used in the diagnosis of disorders of calcium metabolism and the parathyroid gland. The AquaLite® Intact PTH assay is for in vitro diagnostic use.

Device Description

The AquaLite® Intact PTH Bioluminescent Immunoassay Kit uses a goat polyclonal anti-PTH antibody that is pre-coated onto polystyrene tubes (solid phase). Serum samples, appropriate calibrators, and controls, are pipetted (100uL) into the pre-coated tubes. A second goat polyclonal anti-PTH antibody covalently linked to AquaLite® (150µL) is then added to the tubes. Intact PTH in the sample simultaneously combines with anti-PTH antibody on the solid phase and conjugate antibody to form an immune complex or "sandwich" bound to the solid phase. Complex formation is complete after a 120-minute incubation period at room temperature (18° to 25°C) on a standard orbital shaker. The tubes are then washed to remove unbound conjugate.

The washed tubes are placed in a luminometer that is capable of reading a triggered. flash-type reaction in 12 x 75 mm tubes. Injection of the calcium trigger buffer causes AquaLite® to oxide its self-contained luciferin molecule, producing a flash of light which is measured by the luminometer. The intensity of the light emitted from antibody bound to the tubes is directly proportional to the concentration of intact PTH in the sample. To calculate results, the luminometer uses a cubic spline curve fit applied to a logit-log transformation of the light intensity (in relative light units, RLU) of the intact PTH calibrators versus intact PTH concentration (in pg/mL).

AI/ML Overview

Here's a breakdown of the acceptance criteria and study information for the SeaLite Sciences, Inc. AquaLite® Intact PTH device, based on the provided text:

Acceptance Criteria and Reported Device Performance

Criteria	Acceptance Criteria or Description	Reported Device Performance
Sensitivity	Detection limit of the assay (mean signal of zero calibrator + 2 SD)	0.7 pg/mL
Specificity	Recognition of distinct segments of intact (1-84) PTH; limited cross-reactivity with fragments	- 1-34 fragment (400 pg/mL): 50% inhibition - 39-84 fragment (100,000 pg/mL): 0% inhibition - 53-84 fragment (100,000 pg/mL): 0% inhibition - 39-68 fragment (100,000 pg/mL): 0% inhibition - 44-68 fragment (100,000 pg/mL): 0% inhibition
High Dose Hook Effect	No hook effect at high concentrations of intact PTH	No high dose hook effect prior to 100,000 pg/mL
Precision	Intra-assay: Low coefficient of variation (CV) within a single assay	- PTH Level 26.10 pg/mL: 6.95% CV - PTH Level 173.71 pg/mL: 5.45% CV
	Inter-assay: Low coefficient of variation (CV) across multiple assays	- PTH Level 51.7 pg/mL: 8.9% CV - PTH Level 332.3 pg/mL: 8.3% CV
Method Comparison	Good correlation with a commercially available chemiluminometric kit for PTH	- Slope: 0.964 - Y-intercept: 10.017 - Correlation coefficient: 0.95
Linearity and Nonparallelism	Consistent recovery across dilutions of human serum samples	- Sample A: Recovery 103-106% - Sample B: Recovery 99-108% - Sample C: Recovery 100-105%
Recovery	Consistent recovery when mixing PTH serum samples in various ratios	- Sample A (2A:1B, 1A:1B, 1A:2B): Recovery 89-93% - Sample C (2C:1D, 1C:1D, 1C:2D): Recovery 90-92%
Overall Performance	Similar and substantially equivalent to other commercially available assays for intact PTH	Data demonstrate similarity and substantial equivalence

Study Details

Sample Size used for the test set and the data provenance:
- Specificity: Not explicitly stated, but involves spiking a sample (17 pg/mL) with PTH fragments.
- Precision:
  - Intra-assay: 20 replicates for each of two commercial control concentrations.
  - Inter-assay: 20 assays (each with duplicate measurements, so a total of 40 measurements) for each of two commercial control concentrations.
- Method Comparison: 57 patient samples.
- Linearity and Nonparallelism: 3 human serum samples, each diluted and assayed in duplicate.
- Recovery: Not explicitly stated, but involved mixing multiple PTH serum samples in various ratios and assaying in duplicate.
- Data Provenance: Studies were conducted at SeaLite Sciences, Inc. The samples for Method Comparison are referred to as "patient samples," but no specific country of origin or whether they were retrospective or prospective is mentioned. Commercial controls and human serum samples were also used.
Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g. radiologist with 10 years of experience):
- Not applicable. This device is an in vitro diagnostic (IVD) assay that measures a biomarker (Intact PTH). The "ground truth" for method comparison is another commercially available chemiluminometric kit, not expert interpretation. For other performance characteristics, the "ground truth" is based on expected values for controls, dilutions, or spiked samples.
Adjudication method (e.g. 2+1, 3+1, none) for the test set:
- Not applicable. This is an IVD assay, not a device that relies on human interpretation requiring adjudication.
If a multi-reader multi-case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance:
- Not applicable. This is an IVD assay, not an AI-assisted diagnostic tool that involves human readers.
If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:
- Yes, the entire study focuses on the standalone performance of the AquaLite® Intact PTH assay (algorithm/device only). The method comparison is against another standalone commercial assay.
The type of ground truth used (expert consensus, pathology, outcomes data, etc.):
- The "ground truth" varies depending on the specific performance characteristic:
  - Sensitivity: Defined by statistical calculation from the zero calibrator.
  - Specificity: Based on expected behavior with known PTH fragments.
  - Precision: Based on repeated measurements of known control samples.
  - Method Comparison: Comparison against a "commercially available chemiluminometric kit for PTH." This kit serves as the reference standard.
  - Linearity and Recovery: Based on calculated expected values after dilution or mixing of samples.
The sample size for the training set:
- Not applicable. This document describes the performance characteristics and validation of a laboratory assay, not a machine learning model that requires a "training set" in the typical sense. The assay is based on chemical reactions and luminosity measurements, not an algorithm that learns from data.
How the ground truth for the training set was established:
- Not applicable, as there is no training set for this type of IVD device.

Summary

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K970483

APR
1 4
1997

510(k) SUMMARY

As described in 21 C.F.R. § 807.92, the following is a summary of the safety and effectiveness of the SeaLite Sciences, Inc. AquaLite® Intact PTH.

GENERAL INFORMATION I.

Trade or proprietary name - SeaLite Sciences, Inc. AquaLite® Intact PTH

Common or usual name - Bioluminescent immunoassay (BLA)

Classification name - PDA has classified parathyroid hormone test systems intended for the measurement of PTH in the diagnosis of disorders of calcium metabolism as Class II devices. 21 C.F.R. §862.1545.

Submitter's Name and Address:	Cathryn N. CambriaDirector, Regulatory Affairsand Quality AssuranceSeaLite Sciences, Inc.3000 Northwoods ParkwaySuite 200Norcross, GA 30071(800) 874-4471, x227
Submission Date:	February 7, 1997
Legally Market Device to WhichClaim Substantial Equivalence:	Nichols Institute

Nichols Institute Intact PTH assay

INDICATIONS FOR USE D.

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measurements are used in the diagnosis of disorders of calcium metabolism and the parathyroid gland. The AquaLite® Intact PTH assay is for in vitro diagnostic use.

DEVICE DESCRIPTION III.

Note: Samples that generate signals greater than the signal from the highest calibrator are off-scale. These samples must be diluted and re-assayed. Remember to multiply the results from diluted samples by the dilution factor used.

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SUMMARY OF STUDIES AND TECHNOLOGICAL CHARACTERISTICS IV.

Studies on SeaLite Sciences, Inc. AquaLite® Intact PTH were conducted at SeaLite Sciences. The results are summarized below:

Performance Characteristics

1. Sensitivity

The sensitivity or detection limit of the AquaLite® Intact PTH is 0.7 pg/mL. Sensitivity is determined by adding the mean signal of twenty (20) replicates of the zero level calibrator plus two (2) standard deviations above this mean. The PTH concentration (pg/mL) associated with this calculated signal is defined as the sensitivity of the assay.

2. Specificity

The AquaLite® Intact PTH captures antibody coated onto the solid phase, and the conjugate antibody recognizes distinct segments of intact (1-84) PTH. A complex bound to the solid phase is formed only with the intact PTH molecule. Cross reactivity of the Aqualite® Intact PTH assay with PTH fragments was determined by spiking a sample containing intact PTH (17 pg/mL) with PTH fragments.

PTH Fragment	Concentration(pg/mL)	% Inhibition
1-34	400	50
39-84	100,000	0
53-84	100,000	0
39-68	100,000	0
44-68	100,000	0

3. High Dose Hook Effect

No high dose hook effect occurs prior to 100,000 pg/mL intact PTH.

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4. Precision

Intra-assay precision. Two serum commercial controls containing PTH (a) at the following concentrations were assayed to determine intra-assay precision. (Total N = 20 per concentration level.)
لاعب العامل المقاربة المقارمة المستوى المنتخب المنتخب المنتخب المنتخب المنتخب المنتخب المنتخب المنتخب المنتخب المنتخب المنتخب المنتخب المنتخب المنتخب المنتخب المنتخب المنتخب

PTH Level (pg/ml)	% CV
26.10	6.95%
173.71	5.45%

(b) Inter-assay precision. Two serum controls containing prolactin at the following concentrations were assayed in 20 assays. A new standard curve was generated for each assay (n=2x20=40).

PTH Level (pg/ml)	% CV
51.7	8.9%
332.3	8.3%

ડ. Method Comparison

The AquaLite® Intact PTH was used to assay PTH in patient samples (N=57) that were previously assayed by a commercially available chemiluminometric kit for PTH. Correlation by linear regression analysis gave a slope of 0.964 with a y- intercept of 10.017. The correlation coefficient was 0.95.

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6. Linearity and Nonparallelism

Three human serum samples containing the levels of endogenous PTH shown below were diluted as indicated using Calibrator A (0 pg/mL) and assayed in duplicate using AquaLite® Intact PTH. All concentrations are in pg/mL.

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মাধ্যমান

SampleID	DilutionFactor	PTH Found(pg/mL)	PTHExpected(pg/mL)	Recovery(%)
A	Undiluted1:21:41:8	37.419.99.75.0	---18.79.44.7	---106103106
B	Undiluted1:21:41:8	85.746.422.910.6	---42.921.410.7	---10810799
C	Undiluted1:21:41:8	709.0354.0182.092.6	---354.0177.088.6	---100103105

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7. Recovery

PTH serum samples were mixed in 2:1, 1:1 and 1:2 ratios and assayed in duplicate. All values are in pg/mL. ·

Sample	Dilution	PTH Observed	PTH Expected	% Recovered
A	UndilutedA	4.0	---	---
A	2A:1B	24.9	28.0	89
A	1A:1B	37.5	40.2	93
A	1A:2B	48.2	52.0	93
B	Undiluted B	76.4	---	---
C	Undiluted C	15.0	---	---
C	2C:1D	52.0	58.0	90
C	1C:1D	71.0	79.0	90
C	1C:2D	92.0	100	92
D	Undiluted D	143.0	---	---

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V. POTENTIAL ADVERSE EFFECTS OF THE DEVICE ON HEALTH

Use Universal Precautions. No known test method can offer complete assurance that products derived from human serum are pathogen-free: therefore, handle all materials of human origin as though they were potentially infectious.

Sodium azide is used as a preservative. This preservative may react with metallic plumbing to from explosive metal azides. Flush with large volumes of water when disposing of materials containing sodium azide.

As an in vitro diagnostic test, there are not direct adverse effects on the health of a patient from the use of this product. However, failure of the device to perform as indicated, the contamination of reagents, the use of reagents past the labeled expiration dates, the use of improper specimens, or human error during the performance of the test may lead to erroneous results and possible improper patient management.

VI. CONCLUSIONS DRAWN FROM STUDIES

The data from the studies conducted demonstrated that the performance of SeaLite Sciences, Inc. AquaLite® Intact PTH is similar and substantially equivalent to that of other commercially available assays for intact PTH.

Regulation Number and Section

§ 862.1545 Parathyroid hormone test system.

(a)
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.(b)
Classification. Class II.