Immunoassay for the in vitro quantitative determination of thyrotropin in human serum and plasma. Measurements of TSH are used in the diagnosis of thyroid and pituitary disorders.

The electrochemiluminescence immunoassay "ECLIA" is intended for use on cobas e immunoassay analyzers.

Device Description

The Elecsys TSH immunoassay makes use of a sandwich test principle using monoclonal antibodies specifically directed against human TSH. The antibodies labeled with ruthenium complex) consist of a chimeric construct from human and mouse specific components. The Elecsys TSH immunoassay is used for the in vitro quantitative determination of thyroid stimulating hormone in human serum and plasma. It is intended for use on the cobas e immunoassay analyzers.

AI/ML Overview

The Elecsys TSH device is an immunoassay for the in vitro quantitative determination of thyrotropin in human serum and plasma, used in the diagnosis of thyroid and pituitary disorders. It is an electrochemiluminescence immunoassay (ECLIA) intended for use on cobas e immunoassay analyzers. The key change in the updated device is a two-step approach to block biotin interference by adding an antibody to bind free biotin in the sample and changing the linker on the biotinylated capture antibody.

Here's an analysis of the acceptance criteria and the study that proves the device meets them:

1. A table of acceptance criteria and the reported device performance

The document provides performance data across various non-clinical studies. The acceptance criteria are generally implied by "All samples met the predetermined acceptance criterion" or "All lots met the predetermined acceptance criterion" for studies like precision, LoB, LoD, LoQ, and linearity. For interference studies, the "No interference seen up to" values represent the performance vs. a defined limit. For lot-to-lot reproducibility, the comparability of SDs and CVs implicitly confirms acceptance. For method comparison, the statistical results (slope, intercept, correlation coefficient, bias) are compared against internal acceptance criteria.

Clinical / Technical Feature	Acceptance Criteria (Explicit or Implied)	Reported Device Performance
Repeatability & Intermediate Precision	All samples met the predetermined acceptance criterion.	CVs for repeatability ranged from 0.7% to 3.4%. CVs for intermediate precision ranged from 1.5% to 11.2%.
Lot-to-Lot Reproducibility	Calculated SDs and CVs for multiple lots comparable to single lot precision study.	Calculated SDs and CVs for multiple lots were comparable.
Limit of Blank (LoB)	All lots met the predetermined acceptance criterion.	0.0025 µIU/mL
Limit of Detection (LoD)	All lots met the predetermined acceptance criterion.	0.005 µIU/mL
Limit of Quantitation (LoQ)	All lots met the predetermined acceptance criterion.	0.005 µIU/mL
Linearity/Assay Reportable Range	All deviations within predetermined acceptance criteria.	Linear in the range from 0.004 - 102 µIU/mL.
High Dose Hook Effect	No hook effect observed up to a specified concentration.	No hook effect up to 1000 µIU/mL TSH.
Biotin Interference (Endogenous)	Biotin interference not exceeding a specified threshold.	No biotin interference in serum concentrations up to 1200 ng/mL. (Previous limitation was ≤ 102 nmol/L or ≤ 25 ng/mL).
Lipemia (Intralipid) Interference	No interference seen up to 1500 mg/dL.	No interference seen up to 2000 mg/dL.
Hemoglobin Interference	No interference seen up to 1000 mg/dL.	No interference seen up to 1000 mg/dL.
Bilirubin Interference	No interference seen up to 41 mg/dL.	No interference seen up to 66 mg/dL.
Rheumatoid Factor (RF) Interference	No interference seen up to 1500 IU/mL.	No interference seen up to 1500 IU/mL.
Immunoglobulin (IgG) Interference	No interference seen up to 2 g/dL.	No interference seen up to 3.98 g/dL.
Immunoglobulin (IgM) Interference	No interference seen up to 0.5 g/dL.	No interference seen up to 0.72 g/dL.
Analytical Specificity (Cross-Reactivity)	All cross-reactivities met the predefined acceptance criterion at the specified concentration.	LH, FSH, hCG showed 0.000% cross-reactivity at high concentrations; hGH not detectable.
Exogenous Interferences (Drugs)	Each compound found to be non-interfering at the drug concentration.	All 30 tested drugs (commonly and specially used) showed no significant interference at concentrations at least 3x maximum daily doses (or 1x for some).
Sample Matrix Comparison	Regression analysis (Passing/Bablok) data consistent with acceptance criteria for various plasma types and different separating gels.	Slope (0.976 - 0.983), Intercept (-0.0006 - -0.021), Correlation (0.999 - 1.00) for serum vs. plasma. Recovery acceptable for PST/SST.
Method Comparison to Predicate	All data met predefined acceptance criteria for agreement between candidate (updated assay) and predicate (current assay).	Passing-Bablok: Slope 0.974, Intercept -0.0002, Correlation 0.999. Bias at 0.27 µIU/mL: -2.7%, Bias at 4.2 µIU/mL: -2.6%.
Stability	Pre-specified acceptance criteria were met.	Stability data supports Roche Diagnostic's claims as reported in package inserts.

2. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)

Precision (Repeatability & Intermediate Precision): The test set involved 2 replicates per run for 21 days, across 2 runs per day, for PreciControl Universal, PC Thyro Sensitive, and 5 human serum samples. This is a prospective study design for precision. Sample types were native, single human donors as well as pools.
Lot-to-Lot Reproducibility: 2 replicates of each of 5 human serum samples per run, 2 runs per day, for 21 days (7 days per lot, n=28 determinations per lot). Prospective design. Sample types were native, single human donors as well as pools.
Limit of Blank (LoB): Five blank samples with two replicates each per run, for 6 runs on ≥ 3 days (total 60 determinations for analyte free samples). Prospective design.
Limit of Detection (LoD): Five low analyte samples with two replicates each per run, for 6 runs on ≥ 3 days (total 60 replicates per sample per reagent lot). Prospective design.
Limit of Quantitation (LoQ): 25 replicates per sample per reagent lot, over 5 days (1 run per day). Prospective design.
Linearity/Assay Reportable Range: Three high analyte human serum samples were diluted and measured in 3-fold determination within a single run. Prospective design.
High Dose Hook Effect: Three human serum samples spiked with analyte, dilution series performed, measured in one-fold determination. Prospective design.
Endogenous Interference: Varied by interferent. For Biotin, Lipemia, Hemoglobin, Bilirubin, RF, IgG, IgM, samples were spiked with interfering substances and diluted into a dilution pool in 10% increments. The number of individual samples/pools is not explicitly stated but implies multiple. Prospective design.
Analytical Specificity/Cross-Reactivity: A native human serum sample pool was used for each potential cross-reacting compound. Prospective design.
Exogenous Interferences (Drugs): Two human serum samples (native serum pools) were used. Prospective design.
Sample Matrix Comparison: A minimum of 56 serum/plasma pairs per sample material (Li-heparin, K2-EDTA, K3-EDTA plasma) were tested in singleton. For PST/SST, blood from five donors was used, measured in duplicate. Prospective design.
Method Comparison to Predicate: 138 samples (129 native human serum samples and 9 diluted human serum samples, single donors as well as pools diluted) were measured in singleton. Prospective design.

Data Provenance: The document does not explicitly state the country of origin for the human serum and plasma samples. However, the manufacturer, Roche Diagnostics, operates globally with establishments in Mannheim and Penzberg, Germany, and Indianapolis, USA. The studies typically indicate the use of "human serum" or "human serum samples" without further geographic specification. All described studies appear to be prospective experimental designs conducted in a laboratory setting for device validation.

3. 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)

This device is an in vitro diagnostic immunoassay testing for a quantifiable biomarker (TSH), not an imaging device or a device requiring expert interpretation of complex clinical data to establish ground truth for its performance characteristics. The ground truth for such assays is established through analytical methods and reference standards (e.g., spectrophotometry for linearity, spiked samples for interference, reference materials for precision, comparison to a predicate device). No human experts are used to "establish primary ground truth" in the sense of clinical diagnosis for these analytical performance studies. The ground truth is the actual concentration of the analyte, or the known characteristics of the samples (e.g., spiked amount of interferent).

4. Adjudication method (e.g. 2+1, 3+1, none) for the test set

Not applicable. As described above, this is an in vitro diagnostic analytical performance study, not a clinical study requiring adjudication of diagnoses or interpretations by experts.

5. 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 device is an automated immunoassay, an in vitro diagnostic (IVD) test, not an imaging device or AI-driven diagnostic tool that would involve human "readers" or AI assistance.

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

Yes, the studies described are all standalone performance studies of the Elecsys TSH immunoassay system. It's an automated device (cobas e immunoassay analyzer) that provides quantitative results without human intervention in the measurement process itself, beyond sample loading and general operation/maintenance.

7. The type of ground truth used (expert consensus, pathology, outcomes data, etc)

The ground truth used for these analytical studies includes:

Known concentrations: For LoB, LoD, LoQ, and linearity, the samples are either analyte-free, at known low concentrations, or dilutions from known high concentrations.
Spiked samples: For interference studies (endogenous and exogenous), known amounts of interfering substances are added to samples.
Reference materials/standards: For precision, controls with defined concentrations are used. Traceability is to the 2nd IRP WHO Reference Standard 80/558.
Comparison to a legally marketed predicate device: For method comparison, the results of the new device are compared quantitatively to those of the predicate device.
Clinical samples (native human serum/plasma): These are used to assess the device's performance across a range of physiological concentrations and in real-world matrices for studies like precision, linearity, and matrix comparison.

8. The sample size for the training set

This document describes a 510(k) submission for a revised immunoassay, not a machine learning or AI-based device. Therefore, there is no "training set" in the context of algorithm development. The development of the assay itself would have involved extensive R&D and analytical testing to optimize reagents and protocols, but this is distinct from training an AI model on a dataset.

9. How the ground truth for the training set was established

Not applicable, as there is no "training set" in the AI/ML context for this device. The assay's performance characteristics are established through the non-clinical studies detailed in the summary.

Summary

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April 16, 2019

Roche Diagnostics Edie Eads Regulatory Affairs Program Manager 9115 Hague Road Indianapolis, IN 46250

Re: K190773

Trade/Device Name: Elecsys TSH Regulation Number: 21 CFR 862.1690 Regulation Name: Thyroid stimulating hormone test system Regulatory Class: Class II Product Code: JLW Dated: March 25, 2019 Received: March 26, 2019

Dear Edie Eads:

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. Although this letter refers to your product as a device, please be aware that some cleared products may instead be combination products. The 510(k) Premarket Notification Database located at https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm identifies combination product submissions. 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. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.

If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. 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

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requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part 801 and Part 809); medical device reporting of medical device-related adverse events) (21 CFR 803) for devices or postmarketing safety reporting (21 CFR 4, Subpart B) for combination products (see https://www.fda.gov/CombinationProducts/GuidanceRegulatoryInformation/ucm597488.htm); good manufacturing practice requirements as set forth in the quality systems (OS) regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.

Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR Part 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to http://www.fda.gov/MedicalDevices/Safety/ReportaProblem/default.htm.

For comprehensive regulatory information about mediation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/MedicalDevices/DeviceRegulationandGuidance/) and CDRH Learn (http://www.fda.gov/Training/CDRHLearn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See the DICE website (http://www.fda.gov/DICE) for more information or contact DICE by email (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).

Sincerely.

Courtney H. Lias, Ph.D. for Director Division of Chemistry and Toxicology Devices Office of In Vitro Diagnostics and Radiological Health Center for Devices and Radiological Health

Enclosure

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Indications for Use

510(k) Number (if known) K190773

Device Name Elecsys TSH

Indications for Use (Describe)

Immunoassay for the in vitro quantitative determination of thyrotropin in human serum and plasma. Measurements of TSH are used in the diagnosis of thyroid and pituitary disorders.

The electrochemiluminescence immunoassay "ECLIA" is intended for use on cobas e immunoassay analyzers.

Type of Use (Select one or both, as applicable)

✓ Prescription Use (Part 21 CFR 801 Subpart D)
❏ Over-The-Counter Use (21 CFR 801 Subpart C)

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Elecsys TSH K190773 510(k) Summary

This summary of 510(k) safety and effectiveness information is being submitted in accordance with the requirements of 21 CFR 807.92. In accordance with 21 CFR 807.87, Roche Diagnostics hereby submits official notification as required by Section 510(k) of the Federal Food, Drug and Cosmetics Act of our intention to market the device described in this Premarket Notification 510(k).

The purpose of this Traditional 510(k) Premarket Notification is to obtain FDA review and clearance for the Elecsys TSH.

Submitter Name	Roche Diagnostics
Address	9115 Hague RoadP.O. Box 50416Indianapolis, IN 46250
Contact	Edie EadsPhone: (317) 521-4668Fax : (317) 521-2324Email : edie.eads@roche.comSecondary Contact: Tammy DeanPhone: (317) 521-3978Fax : (317) 521-2324Email: tammy.dean@roche.com
Date Prepared	March 25, 2019
Proprietary Name	Elecsys TSH
Common Name	TSH
Classification Name	Radioimmunoassay, thyroid-stimulating hormone
Product Codes, Regulation Numbers	JLW, 21CFR862.1690
Predicate Device(s)	Elecsys TSH (current version)
Establishment Registration	For the Elecsys TSH, the establishment registrationnumber for Roche Diagnostics GmbH inMannheim, Germany is 9610126, and for Penzberg,Germany, 9610529.The establishment registration number for RocheDiagnostics in the United States is 1823260.

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1. DEVICE DESCRIPTION

1.1. Reagents

The reagent working solutions include: Rack Pack (kit placed on the analyzer)

. M: Streptavidin-coated microparticles, 1 bottle, 14.1 mL: Streptavidin-coated microparticles 0.72 mg/mL; preservative.
. R1: Anti-TSH-Ab~biotin, 1 bottle, 15.8 mL: Biotinylated monoclonal anti TSH antibody (mouse) 2.0 mg/L; phosphate buffer 100 mmol/L, pH 7.2; preservative.
R2: Anti-TSH-Ab~Ru(bpy), 1 bottle, 13.9 mL: Monoclonal anti TSH antibody . (mouse/human) labeled with ruthenium complex 1.5 mg/L; phosphate buffer 100 mmol/L, pH 7.2; preservative.

The following changes are proposed to block the interference of biotin with the Elecsys TSH assay. Briefly, Roche is taking a two-step approach by adding an antibody to bind free biotin in the sample, and changing the linker on the biotinylated capture antibody.

For the neutralization of free biotin in serum and plasma, Roche developed an antibody which binds to free biotin. The antibodies are specific for free biotin and do not bind to, or interact with, the biotin-linker conjugates.

In the updated biotinylated antibody conjugate, the distance between biotin and the reactive MEA group is elongated by a PEG spacer which provides the coupled biotin more flexibility for the interaction with the Streptavidin matrix. No change is made to the antibody (immunologically reactive component) which still recognizes the same epitope.

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2. INDICATIONS FOR USE

Immunoassay for the in vitro quantitative determination of thyrotropin in human serum and

plasma. Measurements of TSH are used in the diagnosis of thyroid and pituitary disorders.

The electrochemiluminescence immunoassay "ECLIA" is intended for use on the cobas e immunoassay analyzers.

3. TECHNOLOGICAL CHARACTERISTICS

The following table compares the Elecsys TSH (K190773) with its predicate device, Elecsys TSH (K162606).

Feature	Elecsys TSH (K162606)	Elecsys TSH (K190773)
IntendedUse/Indications for Use	Elecsys TSH immunoassay is intended for the invitro quantitative determination of thyrotropin inhuman serum and plasma. Measurements of TSHare used in the diagnosis of thyroid and pituitarydisorders.The Elecsys TSH immunoassay is anelectrochemiluminescence immunoassay"ECLIA", which is intended for use on the cobas eimmunoassay analyzers.	Same.
Detection Method	Electrochemiluminescence "ECLIA"	Same
Applications/Test Time	18 minute	Same
Test Format	Sandwich	Same
Instrument Platform	cobas e immunoassay analyzers	Same
Test Type	Quantitative	Same
Assay Protocol	R1+R2+sample, incubation, +beads,incubation	Same
Handling of R1 and R2	Liquid, ready to use	Same
Pipetting volume	50 µL	Same
Sample Type/Matrix	Human serum, plasma	Same
Sample Anticoagulants	Li-heparin, K2-EDTA and K3-EDTA plasma.	Same
Calibrator	TSH CalSet	Same
Calibration Method	2-point calibration	Same
Feature	Elecsys TSH (K162606)	Elecsys TSH (K190773)
Calibration Interval	Calibration must be performed once per reagent lotusing fresh reagent (i.e. not more than 24 hourssince the cobas e pack was registered on theanalyzer).Calibration interval may be extended based onacceptable verification of calibration by thelaboratory.	Same
Controls	PreciControl Universal andPreciControl TS	Same
Traceability/Standardization	2nd IRP WHO Reference Standard 80/558	Same
Reagent Stability	Store at 2 8 °C. Do not freeze.Store the cobas e pack upright in order to ensurecomplete availability of the microparticles duringautomatic mixing prior to use.Unopened at 2-8°C – up to stated expiration dateOn the cobas e 801 analyzer – 16 weeks	Same
Limitations	Biotin ≤ 102 nmol/L or ≤ 25 ng/mLSamples should not be taken from patientsreceiving therapy with high biotin doses (i.e. > 5mg/day) until at least 8 hours following the lastbiotin administration.	Two-step approach adding anantibody to bind free biotin in thesample and changing the linker onthe biotinylated capture antibody.Biotin ≤ 4912 nmol/L or ≤ 1200 ng/mLBiotin interference This assay hasno biotin interference in serumconcentrations up to 1200 ng/mL.Some studies have shown that serumconcentrations of biotin can reach upto 355 ng/mL within the first hourafter biotin ingestion for subjectsconsuming supplements of 20 mgbiotin per day and up to 1160 ng/mLfor subjects after a single dose of300 mg biotin.
Measuring Range	0.005-100 µIU/mL	Same

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4. NON-CLINICAL PERFORMANCE EVALUATION

The non-clinical performance studies for the Elecsys TSH are summarized below.

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4.1. Repeatability and Intermediate Precision

Precision of the Elecsys TSH assay was evaluated on one cobas e 801 immunoassay analyzer with one reagent lot. The protocol consisted of testing 2 replicates of each control (PreciControl Universal and PC Thyro Sensitive) and human sera (HS) per run, 2 runs per day for 21 days. The samples were run in randomized order on the analyzer. Human serum samples used were all native, single donors as well as pools. Repeatability and Intermediate imprecision were calculated according to EP05-A3. All samples met the predetermined acceptance criterion. The following table summarizes the precision data for the Elecsys TSH.

cobas e 801 analyzer
		Repeatability		Intermediate precision
Sample	Mean µIU/mL	SD µIU/mL	CV %	SD µIU/mL	CV %
Human serum 1	0.015	0.001	3.4	0.002	11.2
Human serum 2	0.281	0.003	1.1	0.005	1.8
Human serum 3	4.09	0.030	0.7	0.090	2.2
Human serum 4	59.8	0.494	0.8	1.10	1.8
Human serum 5	95.6	0.706	0.7	3.81	4.0
PCb) Universal 1	1.39	0.013	1.0	0.021	1.5
PC Universal 2	7.99	0.064	0.8	0.132	1.6
PC Thyro Sensitive	0.176	0.002	1.2	0.004	2.1

4.2. Lot-to-Lot Reproducibility

Lot-to-lot reproducibility of the Elecsys TSH assay was evaluated on one cobas e 801 analyzer using three reagent lots. A precision study was performed for a total of 21 days (7 days for each lot, n = 28 determinations per lot), 2 replicates of each human sera (HS) per run, 2 runs per day. The samples were run in randomized order on the analyzer. Human serum samples used were all native, single donors (human serum 1) as well as pools (human serum 2-5).

Repeatability, Between-Run, Between-Day, Between-Lot and Total imprecision were calculated according to EP05-A3. Calculated SD's and CV's for the multiple lot (reproducibility) study are

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comparable to those of the single lot (intermediate) precision study over 21 days using only one reagent lot indicating that the updated assay performs consistently from lot to lot.

4.3. Limit of Blank (LoB)

LoB of the Elecsys TSH was determined according to CLSI EP17-A2. The experimental design included three reagent lots evaluated on one cobas e 801 analyzer, six runs on ≥ three days, with five blank samples with two replicates each per run. In total, 60 determinations for analyte free samples have been obtained. All lots met the predetermined acceptance criterion. The LoB claim in the labeling will be set to 0.0025 µIU/mL.

4.4. Limit of Detection (LoD)

LoD of the Elecsys TSH was determined according to CLSI EP17-A2. The experimental design included three reagent lots evaluated on one cobas e 801 analyzer, six runs on ≥ three days, with five low analyte samples with two replicates each per run. Sixty (60) replicates per sample per reagent lot were run. All lots met the predetermined acceptance criterion. The LoD claim in the labeling will be set to 0.005 µIU/mL.

4.5. Limit of Quantitation (LoQ)

LoQ of the Elecsys TSH was determined according to CLSI EP17-A2. The experimental design included three reagent lots evaluated on one cobas e 801 analyzer for 5 days, one run per day. There were 25 replicates per sample per reagent lot. The LoQ claim in the labeling will be set to 0.005 µIU/mL.

4.6. Linearity/Assay Reportable Range

Linearity of the Elecsys TSH assay was assessed on the cobas e 801 analyzer according to CLSI EP06-A. Three high analyte human serum samples were diluted and concentrations covering the measuring range were measured. Samples were assayed in 3-fold determination within a single run. All deviations were within predetermined acceptance criteria. Linearity for serum samples was confirmed in the range from 0.004 - 102 µIU/mL.

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4.7. High Dose Hook Effect

The high-dose hook effect of the Elecsys TSH assay was assessed on the cobas e 801 analyzer in one-fold determination. Three human serum samples were spiked with analyte to achieve high TSH concentrations. For each sample, a dilution series was performed. No hook effect up to 1000 µIU/mL TSH.

4.8. Endogenous Interference

The purpose of this study was to evaluate endogenous substances for potential interference with the parameters measured with the Elecsys TSH on the cobas e 801 analyzer.

Biotin: One aliquot of each serum sample was spiked with the interfering substance, another aliquot was spiked with the same volume of isotonic NaCl solution (dilution pool). The interfering pool was then diluted into the dilution pool in 10 % increments. The recovery for each sample was calculated by comparison to the reference (unspiked) sample. The claim in the package insert will be set to ≤ 1200 ng/mL.

Lipemia (Intralipid): One aliquot of each serum sample was spiked with the interfering substance, and another aliquot was spiked with the same volume of isotonic NaCl solution (dilution pool). The interfering pool was then diluted into the dilution pool in 10% increments. The recovery for each sample was calculated by comparison to the reference (unspiked) sample. The claim in the package insert will be set to ≤ 1500 mg/dL.

Hemoglobin: Fresh hemolysate was prepared from fresh EDTA or heparin blood. One aliquot of each serum sample was spiked with the hemolysate (interfering pool), another aliquot was spiked with the same volume of isotonic NaCl solution (dilution pool). The interfering pool was then diluted into the dilution pool in 10% increments. The claim in the package insert will be set to ≤ 1000 mg/dL.

Bilirubin: One aliquot of each serum sample was spiked with the interfering substance, and another aliquot with was spiked with the same volume of the solvent (0.1 mol/L NaOH) of the interfering substance (dilution pool). The interfering pool was then diluted into the dilution pool in 10% increments. The claim in the package insert will be set to ≤ 41 mg/dL.

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Rheumatoid Factor (RF): One aliquot of each serum sample was spiked with the interfering substance, and another aliquot with the same volume of the solvent (buffer matrix) of the interfering substance (dilution pool). The interfering pool was then diluted into the dilution pool in 10% increments. The recovery for each sample was calculated by comparison to the reference sample. The claim in the package insert will be set to < 1500 IU/mL.

Immunoglobulin (IgG, IgM) Interference: One aliquot of each serum sample was spiked with the interfering substance (lyophilisate). In this case, another aliquot without any additives (since the interfering substance is a lyophilisate) is used as dilution pool. The interfering pool was then diluted into the dilution pool in 10% increments. The recovery for each sample was calculated by comparison to the reference sample. The claim in the package insert will be set to ≤ 2 g/dL for IgG and ≤ 0.5 g/dL for IgM.

Interferent	Specification	Interfering substancemeasured up to		No interferenceseen up to
Intralipid® (Lipemia)	≤ 1500	2000	mg/dL	2000	mg/dL
Biotin	≤ 1200	3600	ng/mL	1200	ng/mL
Bilirubin	≤ 41	66	mg/dL	66	mg/dL
Hemoglobin	≤ 1000	1000	mg/dL	1000	mg/dL
Rheumatic Factor	≤ 1500	1500	IU/mL	1500	IU/mL
Human IgG	≤ 2	7	g/dL	3.98	g/dL
Human IgM	≤ 0.5	1	g/dL	0.72	g/dL

4.8.1. Summary of Endogenous Interference Results

4.9. Analytical Specificity/Cross-Reactivity

The effect on quantitation of analyte in the presence of potential cross-reacting compounds using the Elecsys TSH was determined on the cobas e 801 analyzer using a native human serum sample pool. For each potential cross-reacting compound a human serum sample with a low concentration level of TSH was tested. Results from these spiked serum samples were matched against the unspiked references and the % cross-reactivity was calculated. All cross-reactivities met the predefined acceptance criterion at the specified concentration level of the corresponding cross reactant.

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Cross-reactant	Concentration tested (µU/mL)	Cross-reactivity %
LH	10000	0.000
FSH	10000	0.000
hGH	1000	n.d.
hCG	50000	0.000

n.d. = not detectable

4.10. Exogenous Interferences - Drugs

The effect on quantitation of analyte in the presence of drugs was determined by comparing values obtained from samples spiked with 17 commonly and 13 specially used pharmaceutical compounds with the reference sample (unspiked). Two human serum samples (native serum pools) were used and tested on the cobas e 801 analyzer. The drug concentrations tested correspond at least to the three times maximum daily doses (or the one-time maximum daily dose, respectively). Drug interferences are measured based on recommendations given in CLSI guidelines EP7-ED3 and EP37-ED1 and other published literature. For all drugs tested, the specification was met as each compound was found to be non-interfering at the drug concentration.

Potential interfering commonly used drugs	Highest interferent concentration tested at which no significantinterference was observed (mg/L)
Acetylcysteine	150
Acetylsalicylic acid	30
Ampicilin-Na	75
Ascorbic acid	52.5
Cefoxitin	750
Doxycycline	18
Heparin	3300 IU/L
Levodopa	7.5
Methyldopa	22.5
Metronidazole	123

Table 1:	Common Drugs
----------	--------------

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Potential interfering commonly used drugs	Highest interferent concentration tested at which no significantinterference was observed (mg/L)
Rifampicin	48
Acetaminophen	156
Cyclosporine	1.8
Ibuprofen	219
Theophylline	60
Phenylbutazone	321
Itraconazole	10

Table 2: Special Drugs

Drug	Concentration tested mg/L
Iodide	0.2
Carbimazole	30
Methimazole	80
Propylthiouracil	60
Perchlorate	2000
Propranolol	240
Amiodarone	200
Prednisolone	100
Hydrocortisone	200
Fluocortolone	100
Octreotide	0.3
Levothyroxine	0.25
Liothyronine	0.075

Sample Matrix Comparison 4.11.

The effect on quantitation of analyte in the presence of anticoagulants with the Elecsys TSH immunoassay was determined by comparing values obtained from samples (native human serum samples, single donors as well as pools) drawn into serum and Li-Heparin, K2-EDTA, K3-EDTA

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plasma tubes. A minimum of 56 serum/plasma pairs per sample material were tested in singleton with one reagent lot on one cobas e 801 analyzer. Data were evaluated using a regression analysis according to Passing/Bablok.

Serum/Li-heparin
	Passing/Bablok
N	56
Range	0.009 – 96.2 µIU/mL
Slope	0.983
Intercept	-0.0006
Correlation coefficient r	0.999
Bias at 0.2 µIU/mL	-1.9 %
Bias at 2.5 µIU/mL	-1.7 %
Serum/K2-EDTA
N	58
Range	0.009 – 96.2 µIU/mL
Slope	0.976
Intercept	-0.0006
Correlation coefficient r	1.00
Bias at 0.2 µIU/mL	-2.6 %
Bias at 2.5 µIU/mL	-2.4 %
Serum/K3-EDTA
N	58
Range	0.009 – 96.2 µIU/mL
Slope	0.981
Intercept	-0.021
Correlation coefficient r	1.00
Bias at 0.2 µIU/mL	-9.7 %
Bias at 2.5 µIU/mL	-2.4 %

Plasma/Serum separation tubes (PST/SST) from 3 separate manufacturers and blood from five donors were used. Measurements were performed in duplicate with one reagent lot and evaluated on the basis of recovery relative to the serum/plasma tube without separating gel (reference).

The resulting data support the package insert claim that the following sample types are acceptable to use for Elecsys TSH assay: Serum collected using standard serum tubes or tubes containing separating gel, Li-Heparin, K2-EDTA, K3-EDTA plasma and Plasma tubes containing separating gel.

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Method Comparison to Predicate 4.12.

A method comparison was performed using the Elecsys TSH updated assay (candidate device, Y) and the Elecsys TSH current assay (predicate device, X) to assess the bias between the two assays. A total of 138 samples (129 native human serum samples and 9 diluted human serum samples, single donors as well as pools diluted) were measured in singleton on the cobas e 801 analyzer in one run covering the entire measuring range. Results for the method comparison are summarized in the following table, all data met predefined acceptance criteria:

	Passing-Bablok	Linear Regression*
N	138
Range (µIU/mL)	0.006 – 99.2
Slope(LCL / UCL)	0.974(0.958 / 0.984)	0.944(0.936 / 0.952)
Intercept (µIU/mL)(LCL / UCL)	-0.0002(-0.0019 / 0.0022)	0.089(-0.106 / 0.284)
Correlation coefficientPearson (r)	0.999	-
Kendall (tau)	-	0.972
Bias at 0.27 µIU/mL(LCL / UCL)	-2.7(-3.8 / -1.8)	27.3(-44.5 / 99.1)
Bias at 4.2 µIU/mL(LCL / UCL)	-2.6(-4.2 / -1.7)	-3.5(-7.9 / 0.9)

*not specified

4.13. Stability

The stability studies were performed and the pre-specified acceptance criteria were met. The stability data supports Roche Diagnostic's claims as reported in the package inserts.

4.14. Substantial Equivalence

The Elecsys TSH immunoassay (updated assay, Mat. No. 08443432190) is substantially equivalent to the Elecsys TSH immunoassay (current assay, Mat. No. 07028091190).

Regulation Number and Section

§ 862.1690 Thyroid stimulating hormone test system.

(a)
Identification. A thyroid stimulating hormone test system is a device intended to measure thyroid stimulating hormone, also known as thyrotrophin and thyrotrophic hormone, in serum and plasma. Measurements of thyroid stimulating hormone produced by the anterior pituitary are used in the diagnosis of thyroid or pituitary disorders.(b)
Classification. Class II.