Solid phase enzyme-linked immunosorbent assay (ELISA) based on the competition principle. An unknown amount of antigen present in the sample and a fixed amount of enzyme labelled antigen compete for the binding sites of the antibodies coated onto the wells. After incubation the wells are washed to stop the competition reaction. After the substrate reaction the intensity of the developed color is inversely proportional to the amount of the antigen in the sample. Results of samples can be determined directly using the standard curve.

AI/ML Overview

Here's an analysis of the acceptance criteria and the study proving device performance for the IBL Cortisol ELISA, based on the provided text:

Acceptance Criteria and Device Performance for IBL Cortisol ELISA

1. Table of Acceptance Criteria and Reported Device Performance

The submission document for K062626 does not explicitly state pre-defined acceptance criteria in a dedicated section. However, the performance data presented implicitly serves as the criteria the device met for clearance. Based on the "Device Performance" section, the following can be inferred as the de-facto acceptance measurements:

Performance Metric	Acceptance Criteria (Inferred)	Reported Device Performance
Shelf Life (Complete Kit)	At least 9 months at 2-8 °C (based on predicate)	9 months at 2-8 °C
Method Comparison (vs. IBL-Luminescence IA)	High correlation (r value close to 1) and acceptable linear regression for both serum and saliva samples.	Saliva: IBL-ELISA = 0.92 x IBL-Luminescence IA + 0.06 µg/dL; r = 0.995 (n = 130) Serum: IBL-ELISA = 1.17 x IBL-Luminescence IA - 2.2 µg/dL; r = 0.997 (n = 129)
Method Comparison (vs. GC/MS)	High correlation (r value close to 1) and acceptable linear regression for serum samples.	Serum: IBL-ELISA = 0.97 x GCMS + 2.3 µg/dL; r = 0.982 (n = 33)
Interference	Minimal effect (+/- 20% of expected) on test results at specified concentrations.	Hemoglobin (4.0 mg/mL): 0.06; 0.33; 0.62 µg/dL (Cortisol)Bilirubin (0.5 mg/mL): 0.07; 0.35; 0.63 µg/dL (Cortisol)Triglyceride (30 mg/mL): 0.07; 0.40; 0.75 µg/dL (Cortisol)Thimerosal (0.50 %): 0.19; 0.25; 0.34 µg/dL (Cortisol)Blood (0.125 %): 0.09; 0.26 µg/dL (Cortisol)NaN3 (0.60 %): 0.23; 0.31 µg/dL (Cortisol) (All met the < 20% effect criteria, implied by "do not have a significant effect")
Analytical Specificity (Cross-Reactivity)	Low cross-reactivity for other substances (e.g., < 0.01%). Specific values for known cross-reactants.	Prednisolone: 29%11-Desoxy-Cortisol: 16%Corticosterone: 2.4%Cortisone: 3.3%Prednisone: 2.2%17α-OH-Progesterone: 1.2%Desoxy-Corticosterone: 0.5%6α-Methyl-17α-OH-Progesterone: 0.3%Other substances tested: < 0.01%
Analytical Sensitivity (Limit of Detection)	A low concentration indicating detection capability.	0.015 µg/dL (Mean signal (Zero-Standard) - 2SD)
Functional Sensitivity	Concentration with < 20% CV.	0.060 µg/dL (Mean Conc. < 20 % CV)
Precision (Intra-Assay & Inter-Assay)	Low Coefficient of Variation (CV%) across different concentrations for both saliva and serum.	Intra-Assay Saliva: 6.4% (0.252 µg/dL), 7.6% (0.312 µg/dL), 3.2% (2.927 µg/dL)Intra-Assay Serum: 11.8% (0.103 µg/dL), 10.7% (0.499 µg/dL), 3.8% (3.421 µg/dL)Inter-Assay Saliva: 9.1% (0.215 µg/dL), 6.9% (0.864 µg/dL), 6.2% (2.638 µg/dL)Inter-Assay Serum: 10.8% (0.094 µg/dL), 10.9% (0.394 µg/dL), 12.0% (0.582 µg/dL)
Linearity	Percent recovery (Rec. %) within an acceptable range across dilutions (e.g., 80-120%).	Saliva: 83-114% (Sample 1), 95-115% (Sample 2), 84-114% (Sample 3) across various dilutions (1:2 to 1:32)Serum: 96-111% (Sample 1), 96-120% (Sample 2), 90-112% (Sample 3) across various dilutions (1:50 to 1:3200). Most values are within the 80-120% range.
Recovery	Percent recovery (Rec. %) within an acceptable range (e.g., 80-120%).	Saliva: 80-119% across three different saliva samples with varying added cortisol concentrations.Serum: 88-113% across three different serum samples with varying added cortisol concentrations. (Most values are within the 80-120% range and are considered acceptable.)

2. Sample Sizes Used for the Test Set and Data Provenance

Method Comparison (vs. IBL-Luminescence IA):
- Saliva: n = 130 samples
- Serum: n = 129 samples
- Data Provenance: Not explicitly stated, but the comparison is against the "Cortisol LIA" which is stated to be "manufactured in same way" as the original submission K052359 (and K010790). This implies a comparison against an existing, legally marketed device, likely using clinical samples. It's not specified if these were retrospective or prospective, nor the country of origin, beyond the manufacturer being in Germany.
Method Comparison (vs. GC/MS):
- Serum: n = 33 samples
- Data Provenance: Samples were obtained from the DGKC (Deutsche Gesellschaft für klinische Chemie, Bonn Germany) quality assessment scheme for hormones. This suggests a reference-based comparison using established samples. The method GC/MS is a recognized reference method.
Interference Studies: The number of unique samples for each interference test is not specified, but each interferent was tested at different cortisol concentrations (e.g., three cortisol levels for hemoglobin, bilirubin, triglyceride, thimerosal, NaN3, and two for blood).
Precision Studies:
- Saliva: n = 20 for functional sensitivity and intra-assay/inter-assay precision.
- Serum (1:50 diluted): n = 20 for functional sensitivity and intra-assay/inter-assay precision.
Linearity & Recovery Studies: The number of individual samples is not explicitly stated beyond "Saliva 1", "Saliva 2", "Saliva 3" (implies 3 unique saliva control/patient samples) and "Serum 1", "Serum 2", "Serum 3" (implies 3 unique serum control/patient samples), which were then diluted or spiked.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications

No human expert "ground truth" was established in the traditional sense for diagnostic interpretation. This device is a quantitative assay.
For method comparison: The ground truth was established by:
- Quantitative results from an existing commercial device (IBL-Luminescence IA)
- Quantitative results from a reference method (GC/MS, Siekmann et al., J.Clin.Chem.Clin.Biochem. 20 (1982) 883-892)
For other performance characteristics (sensitivity, specificity, precision, linearity, recovery): The ground truth is determined by the inherent properties of the samples (e.g., known spikes, dilutions, or intrinsic sample concentrations) and statistical calculations (e.g., means, standard deviations, CVs).

4. Adjudication Method for the Test Set

Not applicable. This is a quantitative assay comparing its output to other quantitative methods or known sample properties, not relying on expert adjudication for a diagnostic classification.

5. If a multi-reader multi-case (MRMC) comparative effectiveness study was done

No. An MRMC study is not relevant for a quantitative diagnostic assay like this ELISA kit, which does not involve human interpretation of images or other subjective data.
The effectiveness is demonstrated by its analytical performance characteristics (accuracy, precision, linearity, etc.) and its correlation with established reference methods.

6. If a standalone (i.e. algorithm only without human-in-the loop performance) was done

Yes. The performance studies presented are for the IBL Cortisol ELISA kit operating in a standalone capacity, without human-in-the-loop performance influencing the measurement itself. While a human operates the ELISA, the reported metrics reflect the assay's chemical and instrumental performance.

7. The Type of Ground Truth Used

Quantitative Reference Methods: For method comparison, the ground truth was the quantitative concentration values obtained from:
- IBL-Luminescence IA (a predicate device)
- Gas Chromatography/Mass Spectrometry (GC/MS) (a recognized reference method and gold standard for some analytes)
Known Sample Properties: For precision, linearity, and recovery, the ground truth was based on:
- Expected concentrations in control samples.
- Calculated concentrations from known dilutions or spiking experiments.
Chemical Characteristics: For analytical sensitivity (LOD) and functional sensitivity, ground truth relates to the assay's intrinsic ability to detect and quantify low concentrations. For cross-reactivity, ground truth is the known concentration of interfering substances and their expected non-reactivity.

8. The Sample Size for the Training Set

Not Applicable in the context of machine learning. This device is a traditional immunoassay kit, not an algorithm that requires a training set. Its "development" would involve optimizing reagents and protocols, not machine learning model training.

9. How the Ground Truth for the Training Set Was Established

Not Applicable. See point 8.

Summary

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K062626

SUMMARY OF SAFETY AND EFFECTIVENESS FOR IBL CORTISOL ELISA

DEC 2 0 2006

Manufacturer:	IBL. Immuno Biological LaboratoriesFlughafenstrasse 52A, D-22335Hamburg, Germany
Contact Information:	Victor HerbstIBL Immuno Biological LaboratoriesFlughafenstrasse 52A, D-22335Hamburg, Germany

Device Name / Classification:

The device trade name is the IBL Cortisol ELISA having FDA assigned name: Cortisol (hydrocortisone and hydroxycorticosterone) test system, 21 CFR, 862.1205, categorized as Class II medical devices for the Clinical Chemistry Panel, as Product Code CGR.

Test Principle

Device Intended Use:

Solid phase enzyme-linked immunosorbent assay for the in-vitro diagnostic quantitative determination of free Cortisol in human saliva and of total Cortisol in diluted serum as an aid in the assessment of Cushing Syndrome and Addison's Disease.

Device Performance

All technical data are included in this 510(k) submission. The normal ranges and stability data will be overtaken from the original Cortisol LIA submission No. K052359 (respectively No. K010790) which is manufactured in same way. All single components keep the same, except the substrate system which uses an ordinary TMB (Tetramethylbenzidine) substrate with a given shelf life of 18months by manufacturer. The shelf lifes are therefore as follows:

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Stability of kit components at (2 - 8 ℃) :

Microtiter strips	12 months
Enzyme conjugate.	9 months
Standard A-G	9 months
Kit control 1, 2	9 months
Wash buffer. Concentrate	12 months
ready to use TMB substrate	18 months
TMB Stop solution	36 months

Therefore the complete Kit will have a shelf life of 9 months at 2 - 8 ℃.

Method comparison

A comparison study was performed using 130 saliva and 1290 serum samples. These samples were tested on the IBL Cortisol ELISA and compared to the Cortiso! LIA, The results from measuring the samples in both methods yielded the following correlation:

MethodComparisonversus LIA		Saliva	$IBL-ELISA = 0.92 x IBL-Luminescence IA + 0.06 µg/dL$	r = 0.995;n = 130
		Serum	$IBL-ELISA = 1.17 x IBL-Luminescence IA - 2.2 µg/dL$	r = 0.997; n = 129

Additionally 33 serum samples from the DGKC (Deutsche Gesllschaft für klinische Chemie, Bonn Germany) quality assessment scheme for hormones which were obtained using a GC/MS method, according to: Siekmann et al., J.Clin.Chem.Clin.Biochem. 20 (1982) 883-892, were used for comparison study to the given GC/MS reference values. The results from measuring the samples yielded the following correlation:

MethodComparisonversus GC/MS	Serum	$IBL-ELISA = 0.97 x GCMS + 2.3 \mu g/dL$	r = 0.982; n = 33
--------------------------------------	-------	------------------------------------------	-------------------

Interference Studies

The following blood components have been tested in serum and saliva and do not have a significant effect (+/- 20 % of expected) on the test results up to the concentrations stated below:

	Serum
	Conc.	Cortisol (µg/dL)
Hemoglobin	4.0 mg/mL	0.06; 0.33; 0.62
Bilirubin	0.5 mg/mL	0.07; 0.35; 0.63
Triglyceride	30 mg/mL	0.07; 0.40; 0.75
	Saliva
	Conc.	Cortisol (µg/dL)
Thimerosal	0.50 %	0.19; 0.25; 0.34
Blood	0.125 %	0.09; 0.26
NaN3	0.60 %	0.23; 0.31

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The overall performance of the IBL Cortisol ELISA is:

: 1

	Substance	CrossReactivity (%)
AnalyticalSpecificity(CrossReactivity)	Prednisolone	29	Cross-reactivityof othersubstancestested< 0.01 %
	11-Desoxy-Cortisol	16
	Corticosterone	2.4
	Cortisone	3.3
	Prednisone	2.2
	17α-OH-Progesterone	1.2
	Desoxy-Corticosterone	0.5
	6α-Methyl-17α-OH-Progesterone	0.3
AnalyticalSensitivity(Limit ofDetection)	0.015 µg/dL	Mean signal (Zero-Standard) - 2SD
FunctionalSensitivity	0.060 µg/dL	Mean Conc. < 20 % CV
		Saliva (n = 20)	Serum (1:50 diluted; n = 20)
Precision	Conc.(µg/dL)	SD(µg/dL)	CV(%)	Conc.(µg/dL)	SD(µg/dL)	CV(%)
Intra-Assay	0.252	0.016	6.4	0.103	0.012	11.8
	0.312	0.024	7.6	0.499	0.053	10.7
	2.927	0.094	3.2	3.421	0.132	3.8
	0.215	0.020	9.1	0.094	0.010	10.8
Inter-Assay	0.864	0.059	6.9	0.394	0.043	10.9
	2.638	0.164	6.2	0.582	0.070	12.0
		Dilution	Saliva		Dilution	Serum
		Meas.(µg/dL)	Rec.(%)		Calc. (1:50)(µg/dL)	Rec.(%)
Linearity		3.035	100		1:50	35.2	100
		1:2	1.259	83	1:100	16.8	96
		1:4	0.635	84	1:200	9.4	107
		1:8	0.340	90	1:400	4.4	101
		1:16	0.184	97	1:800	2.4	111
		1:32	0.108	114	1:1600	1.1	97
		-	0.834	100	1:50	29.6	100
		1:2	0.416	115	1:100	14.4	98
		1:4	0.202	106	1:200	7.5	101
		1:8	0.119	95	1:400	4.4	120
		-	0.602	100	1:50	227.2	100
		1:2	0.254	84	1:100	108.9	96
	1:4	0.146	97	1:200	51.4	90
	1:8	0.082	109	1:400	25.8	91
				1:800	13.4	94
				1:1600	6.5	96
				1:3200	3.6	112

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	Saliva				Serum
Recovery	Conc.	Added	Meas.	Rec.	Conc.	Added	Meas.	Expect.	Rec.
	(µg/dL)	(µg/dL)	(µg/dL)	(%)	(µg/dL)	(µg/dL)	(µg/dL)	(µg/dL)	(%)
	Saliva 1(0.25)		0.04	0.30	104	Serum 1(4.75)	2.0	7.6	6.7	113
			0.08	0.34	105		3.9	8.1	8.7	93
			0.16	0.39	97		7.8	13.7	12.6	109
			0.31	0.61	109		15.6	21.2	20.4	104
			0.63	0.91	104		31.3	38.3	36.0	106
			1.25	1.51	101		62.5	72.0	67.3	107
			2.50	2.19	80		125.0	120.5	129.8	93
	Saliva 2(0.30)		0.03	0.30	91	Serum 2(23.0)	2.0	22.1	25.0	89
			0.06	0.37	103		3.9	23.6	26.9	88
			0.13	0.43	102		7.8	27.6	30.8	89
			0.25	0.57	105		15.6	37.6	38.6	97
			0.50	0.93	116		31.3	56.6	54.3	104
			1.00	1.22	94		62.5	83.1	85.5	97
			2.00	2.05	89		125.0	143.6	148.0	97
	Saliva 3(0.23)		0.03	0.26	97	Serum 3(31.1)	2.0	32.2	33.1	97
			0.06	0.27	92		3.9	34.6	35.0	99
			0.13	0.39	108		7.8	35.8	38.9	92
			0.25	0.50	103		15.6	44.7	46.7	96
			0.50	0.84	114		31.3	59.2	62.4	95
			1.00	1.48	120		62.5	95.6	93.6	102
			2.00	2.65	119		125.0	146.3	156.1	94
MethodComparison	Saliva			IBL-ELISA = 0.92 x IBL-Luminescence IA + 0.06					r = 0.995; n = 130
	Serum			IBL-ELISA = 1.17 x IBL-Luminescence IA - 2.2					r = 0.997; n = 129
				IBL-ELISA = 0.97 x GCMS + 2.3					r = 0.982; n = 33

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Image /page/4/Picture/1 description: The image shows the logo for the U.S. Department of Health & Human Services. The logo features a stylized eagle or bird-like symbol with three curved lines representing its body and wings. The text "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" is arranged in a circular fashion around the bird symbol.

Food and Drug Administration 2098 Gaither Road Rockville MD 20850

Victor Herbst IBL-Hamburg Gmbh Flughafenstrasse 52a Hamburg, D-22335 Germany

Re:

DEC 2 0 2006

K062626 Trade/Device Name: Cortisol ELISA test kit Regulation Number: 21 CFR 862.1205 Regulation Name: Cortisol (Hydrocortisone and Hydroxycortisone) test Regulatory Class: Class II Product Code: CGR Dated: November 28, 2006 Received: November 30, 2006

Dear Mr. Herbst:

We have reviewed your Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food, Drug, and Cosmetic Act (Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration.

If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to such additional controls. Existing major regulations affecting your device can be found in Title 21. Code of Federal Regulations (CFR), Parts 800 to 895. In addition, FDA may publish further announcements concerning your device in the Federal Register.

Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Parts 801 and 809); and good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820).

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Page 2 -

This letter will allow you to begin marketing your device as described in your Section 510(k) premarket notification. The FDA finding of substantial equivalence of your device to a legally marketed predicate device results in a classification for your device and thus, permits your device to proceed to the market.

If you desire specific information about the application of labeling requirements to your device, or questions on the promotion and advertising of your device, please contact the Office of In Vitro Diagnostic Device Evaluation and Safety at (240) 276-0484. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21CFR Part 807.97), You may obtain other general information on your responsibilities under the Act from the Division of Small Manufacturers, International and Consumer Assistance at its toll-free number (800) 638-2041 or (301) 443-6597 or at its Internet address http://www.fda.gov/cdrh/dsma/dsmamain.html.

Sincerely yours,

Jean M, Cooper MS, DVM

Jean M. Cooper, MS. D.V.M. Director Division of Chemistry and Toxicology Office of In Vitro Diagnostic Device Evaluation and Safety Center for Devices and Radiological Health

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Indications for Use

510(k) Number (if known):

K062626

Device Name: Cortisol ELISA test kit

Indications For Use:

The IBL Cortisol enzym linked immunosorbent assay is for the in-vitro-diagnostic quantitative determination of cortisol in human serum and saliva.

The Cortisol ELISA kit is useful as an aid in the differential diagnosis of Cushing syndrome and Addison's disease.

Prescription Use (Part 21 CFR 801 Subpart D) AND/OR

Over-The-Counter Use (21 CFR 801 Subpart C)

(PLEASE DO NOT WRITE BELOW THIS LINE-CONTINUE ON ANOTHER PAGE IF NEEDED)

Concurrence of CDRH, Office of In Vitro Diagnostic Devices (OIVD)

Division Sign-Off

Jivision Sign-Off

Office of In Vitro Diagnostic Device Evaluation and Safety

510(k) K062624

Page 1 of 1

Regulation Number and Section

§ 862.1205 Cortisol (hydrocortisone and hydroxycorticosterone) test system.

(a)
Identification. A cortisol (hydrocortisone and hydroxycorticosterone) test system is a device intended to measure the cortisol hormones secreted by the adrenal gland in plasma and urine. Measurements of cortisol are used in the diagnosis and treatment of disorders of the adrenal gland.(b)
Classification. Class II.