(175 days)
The FREND™ Free T4 Test System is a rapid indirect competitive immunoassay for the quantitation of free thyroxine (FT4) in human serum and lithium heparinized plasma specimens using the FREND™ Free T4 system. Measurements of free thyroxine (FT4) are used in the diagnosis of thyroid disorders. The FREND™ Free T4 Test System is intended for use in clinical laboratories. For in vitro diagnostic use only. The test is not intended for point-of-care facilities.
The FREND™ Free T4 is a rapid fluorescence immunoassay that measures Free T4 in human serum and in lithium heparinized plasma using the FREND™ Free T4 Test System. The FREND™ Free T4 is a single use fluorescence immunoassay designed to quantify the concentration of free thyroxine in serum and lithium heparinized plasma samples, The FREND™ Free T4 test is a two-step competitive immunoassay with gold nanoparticles labeled with T4-specific monoclonal anti-T4- antibody (mouse), T3-BSA labeled with fluorescent nanoparticles, and fluorescence detection by the FREND™ System. The FREND™ Free T4 Test utilizes microfluidic technology and detects immunecomplexes bound to Free T4. A 70ul Sample is first incubated during Step 1 for five minutes at 37 degrees C in the Free T4 Gold AB Tube with monoclonal anti-T4 antibody conjugated with gold nanoparticles. In Step 2, 35 ul of the mixture from Step 1 is manually loaded into the inlet of the cartridge, where it hydrates a T3-BSA fluorescent bead conjugate and migrates along the test strip. During migration the bound Free T4 in the sample and the fluorescent bead conjugates of T3-BSA compete to form antigenantibody complex in the test zone. Unbound T3-BSA fluorescent conjugates flow through and bind to the anti-T4 antibody that is fixed on the surface in the reference zone. Step 2 takes approximately four minutes after which the fluorescent signals in the test and reference zones are measured. Free T4 quantification is based upon the ratio of the intensity of the test and reference zones. A lower ratio of fluorescence is indicative of a higher Free T4 concentration, in other words, the maqnitude of the fluorescence ratio is inversely proportional to the amount of Free T4 in the sample. The free T4 detection range of the FREND™ Free T4 Test System is 0.4 to 6.0 ng/dL. Results are determined via a lot-specific calibration curve which is generated by the manufacturer using a six-point calibration determined from values averaged from five replicates at each level. The established curve is uploaded to the FREND™ System via the Free T4 Code-chip and is valid until the lot expiration date. The established curve is saved in the code-chip and valid until the expiration date of the test cartridge lot. The FREND™ Free T4 Test cartridge is a disposable plastic device that houses the reagents and contains a port or opening (inlet) where the sample is applied. Once the sample is applied, it will mix with the reagents and travel towards the detection area via capillary action. The FREND™ System is a portable, automated FREND™ cartridge reader. The FREND™ System is based on quantitative immunoassay technology capable of quantifying single or multiple analytes by measuring laser-induced fluorescence in a single-use disposable reagent cartridge. The FREND™ cartridge utilizes micro-fluidics lateral flow technology where the analyte of interest in the sample forms immune complexes while moving through the fluidics pathway in the cartridge. The concentration of the analyte of interest in an unknown sample is calculated using the ratio of the fluorescent intensity of the test zone and the reference zone. The FREND™ System is a bench top fluorescence reader containing a touch screen user interface. The System has a slot that accepts the FREND™ Free T4 Test Cartridge (which contains the reagents and sample), and is programmed to analyze the Test when the sample has fully reacted with the on-board in-cartridge reagents. Results of the test are displayed on the screen and can be printed on an optional printer. The FREND™ System software controls the graphical user interface, communication with hardware, database manaqement and data analysis. The software also controls the functions of the mechanical components including the motor, laser, printer control and acquisition of data from the sensor. The user can set the time and date and enter patient ID through the graphic user interface. The user cannot make any changes to the software.
Here's a summary of the acceptance criteria and study details for the FREND™ Free T4 Test System, based on the provided 510(k) submission:
1. Table of Acceptance Criteria and Reported Device Performance
The acceptance criteria are not explicitly stated as pass/fail values in many sections, but rather implied by the statistical analyses meeting CLSI guidelines and demonstrating comparability to the predicate device. The performance data is presented against these implicit standards.
| Performance Metric | Acceptance Criteria (Implied) | Reported Device Performance |
|---|---|---|
| Precision | Repeatability, Between-run, Between-day, Within-laboratory CV% within acceptable limits for a diagnostic assay. | Sample Pool 1 (0.917 ng/dL): Repeatability CV% 7.3, Within-lab CV% 8.1 |
| (Single lot imprecision) | (Based on CLSI EP5-A3 protocol) | Sample Pool 2 (1.850 ng/dL): Repeatability CV% 5.6, Within-lab CV% 6.7 |
| Sample Pool 3 (3.979 ng/dL): Repeatability CV% 4.7, Within-lab CV% 6.5 | ||
| Linearity/Reportable Range | Acceptable linearity across the measuring range. | Linear across 0.11 ~ 7.5 ng/dL (Slope = 0.978, Intercept = -0.0881, R² = 0.9938). Measuring range (0.4 ~ 6 ng/dL) is within this linear range. |
| Detection Limit (LoD) | LoD to support the stated measuring range. | 0.32 ng/dL |
| Limit of Quantitation (LoQ) | LoQ to support the stated measuring range. | 0.36 ng/dL |
| Interference Studies | Recovery between 90% to 110% of expected Free T4. | All tested endogenous substances and pharmaceuticals showed recovery within 90-110%, except for a few instances (e.g., Biotin 94%, Hydrocortisone 90.1% at high Free T4, Iodide 86.8% at high Free T4). RF, HAMA, Avidin, Au-nanoparticles also within range. |
| Cross-Reactivity | No significant cross-reactivity with related substances, except for L-Thyroxine itself. | No significant cross-reactivity (below 0.03%) with tested substances other than L-Thyroxine (T4), which showed 99.44-99.57%. |
| Method Comparison with Predicate Device | Difference between test device and predicate device concentrations less than allowable difference; good correlation. | N=358 samples. Slope: 1.010 (95% CI: 0.992 to 1.028), y-Intercept: 0.057 (95% CI: 0.021 to 0.094), r: 0.986. Range tested: 0.43 ~ 5.99 ng/dL. Concluded to compare favorably. |
| Matrix Comparison | Comparability between serum and lithium heparin plasma. | N=48 paired samples. Passing-Bablok regression: Slope: 1.017 (95% CI: 0.991 to 1.044), y-Intercept: -0.008 (95% CI: -0.055 to 0.0451). Range tested: 0.44 ~ 5.63 ng/dL. Indicated measurement equally well in both matrices. |
2. Sample Size Used for the Test Set and Data Provenance
- Precision Study: 3 serum pools
- Linearity Study: 1 serum base pool diluted to 11 levels
- Interference Studies: Two levels of free T4 for various endogenous substances and pharmaceuticals.
- Cross-Reactivity Study: Two concentrations for various cross-reactants.
- Method Comparison: 358 samples
- Matrix Comparison: 48 paired serum and lithium heparin samples
- Expected Values/Reference Range: 196 normal, apparently healthy adult individuals
The specific country of origin for the test set data is not explicitly stated, but the precision, linearity, interference, and matrix comparison studies were performed at the NanoEnTek laboratory. The method comparison study was performed at a CLIA-certified laboratory testing facility. The clinical samples for the method comparison were evaluated at that CLIA laboratory. The reference range study used samples from 196 normal, apparently healthy adult individuals. The nature of "clinical samples" for the method comparison implies they would be patient samples, and "normal, apparently healthy adult individuals" for the reference range are also patient-like samples. The studies appear to be prospective in nature, as they involve testing the device with specific protocols (e.g., CLSI guidelines).
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications
- None stated for the analytical performance studies. The ground truth for analytical studies (precision, linearity, LoD, LoQ, interference, cross-reactivity) is generally based on the inherent properties of the samples and the performance of established reference methods or spiked concentrations.
- For Method Comparison: The ground truth was established by a predicate device, the Abbott ARCHITECT Free T4 Assay. The number of human experts involved in interpreting results from either the predicate device or the FREND™ Free T4 Test System is not specified, as this is a quantitative immunoassay where results are read by a machine.
4. Adjudication Method for the Test Set
Not applicable for this type of quantitative immunoassay performance study. Ground truth is established by reference methods or defined concentrations, not human adjudication.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, and Effect Size
No, a multi-reader multi-case (MRMC) comparative effectiveness study was not done. This device is a quantitative immunoassay, not an imaging device requiring human interpretation, so MRMC studies are not relevant.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
Yes, the studies described are standalone performance studies for the FREND™ Free T4 Test System. The device is intended for use in clinical laboratories, and the results are quantitatively measured by the FREND™ System directly. There is no human-in-the-loop performance evaluation described beyond standard laboratory procedures for operating the instrument and handling samples.
7. The Type of Ground Truth Used
- Analytical Performance:
- Precision, Linearity, LoD, LoQ, Interference, Cross-reactivity: Ground truth was established by prepared samples with known concentrations, spiking experiments, and measurements against established laboratory protocols and standards (CLSI guidelines).
- Method Comparison: Ground truth was established by the predicate device, the Abbott ARCHITECT Free T4 Assay (K123379). This is a comparison against an existing, legally marketed device.
- Matrix Comparison: Ground truth (or comparative standard) derived from measuring the same analyte in different matrices (serum vs. plasma), with the expectation of comparable results.
8. The Sample Size for the Training Set
The document does not explicitly mention a "training set" in the context of an AI/machine learning algorithm. For this immunoassay, the system's "training" involves the manufacturer-generated lot-specific calibration curve (six-point calibration determined from values averaged from five replicates at each level), which is then uploaded to the FREND™ System via a Code-chip.
9. How the Ground Truth for the Training Set Was Established
As described above, the "ground truth" for the device's operational curve (its calibration) is established by:
- Internal standards prepared according to CLSI C45-A Measurement of Free Thyroid Hormones.
- Gravimetric methods based on L-Thyroxine (Sigma T1775, Cell culture grade).
- Confirmation of calibrator Free T4 levels by measurement on the ARCHITECT i free T4 assay (K123379).
This process ensures that the device's internal calibration accurately reflects known Free T4 concentrations.
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Food and Drug Administration 10903 New Hampshire Avenue Document Control Center - WO66-G609 Silver Spring, MD 20993-0002
February 18,2016
NANOENTEK USA INC % MAUREEN GARNER NEW WORLD REGULATORY SOLUTIONS, INC. 1983 HAZELWOOD ROAD TOMS RIVER, NJ 08753
Re: K152422
Trade/Device Name: FREND™ Free T4 Test System Regulation Number: 21 CFR 862.1695 Regulation Name: Free thyroxine test system Regulatory Class: II Product Code: CEC Dated: December 31, 2015 Received: January 04, 2016
Dear Maureen Garner:
This letter corrects our substantially equivalent letter of February 17, 2016.
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. 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 requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Parts 801 and 809); medical device reporting (reporting of medical device-related adverse events) (21 CFR 803); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820); and if applicable, the
{1}------------------------------------------------
electronic product radiation control provisions (Sections 531-542 of the Act): 21 CFR 1000-1050.
If you desire specific advice for your device on our labeling regulations (21 CFR Parts 801 and 809), please contact the Division of Industry and Consumer Education at its toll-free number (800) 638 2041 or (301) 796-7100 or at its Internet address
http://www.fda.gov/MedicalDevices/Resourcesfor You/Industry/default.htm. 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 the CDRH's Office of Surveillance and Biometrics/Division of Postmarket Surveillance.
You may obtain other general information on your responsibilities under the Act from the Division of Industry and Consumer Education at its toll-free number (800) 638-2041 or (301) 796-7100 or at its Internet address
http://www.fda.gov/MedicalDevices/ResourcesforYou/Industry/default.htm.
Sincerely yours,
Katherine Serrano -S
For : Courtney H.Lias, Ph.D.
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)
Device Name FREND™ Free T4 Test System
Indications for Use (Describe)
The FREND™ Free T4 Test System is a rapid indirect competitive immunoassay for the quantitation of free thyroxine (FT4) in human serum and lithium heparinized plasma specimens using the FREND™ Free T4 system. Measurements of free thyroxine (FT4) are used in the diagnosis of thyroid disorders. The FREND™ Free T4 Test System is intended for use in clinical laboratories. For in vitro diagnostic use only. The test is not intended for point-of-care facilities.
| 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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510(k) Summary
As required by the Safe Medical Devices Act (SMDA) of 1990 and in accordance with 21 CFR §807.92, a 510(k) summary is provided.
A. Applicant
| Company Name: | NanoEnTek, Inc. |
|---|---|
| Address: | 12F 5 Digital-ro, 26-gil, Guro-guSeoul 152-740, KOREA |
| Contact Person: | Sunmi Han |
| Phone Number: | +82-2-6220-7940 |
| Facsimile Number: | +82-2-6220-7721 |
B. 510(k) Preparer Information (Contact Person)
| Company Name: | New World Regulatory Solutions, Inc. |
|---|---|
| Address: | P.O. Box 5374Toms River, New Jersey 08754, USA |
| Contact Person: | Maureen Garner |
| Phone Number: | (732) 779-7422 |
| Facsimile Number: | (732) 270-4829 |
| Email: | NWRSinc@gmail.com |
C. Purpose for Submission:
New Analyte on FREND™ System
D. Measurand:
Free thyroxine
E. Type of Test:
Quantitative, Fluorescence Immunoassay
F. Proprietary and Established Device Name:
FREND™ Free T4 Test System
Regulatory Information: G.
| Common Name: | FREND™ Free T4 (reagent cartridge) |
|---|---|
| Generic Name: | Competitive Immunoassay, Free T4 |
| Regulation Number: | 21 CFR §862.1695 |
| Product Code: | CEC |
| Classification: | Class II |
| Classification Name: | Free thyroxine test system |
| Panel: | Chemistry (75) |
H. Intended Use:
-
- Intended use: See indications for use below:
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-
- Indication(s) for use:
The FREND™ Free T4 Test System, is a rapid indirect fluorescence immunoassay for the quantitative determination of free thyroxine (Free T4) in human serum and lithium heparinized plasma specimens using the FREND™ System. Measurements of free thyroxine (Free T4) are used in the diagnosis of thyroid disorders. The FREND™ Free T4 Test System is intended for use in clinical laboratories. For in vitro diagnostic use only. This test is not intended for point-of-care facilities.
- Indication(s) for use:
-
- Special conditions for use statement(s): For prescription use only.
-
- Special instrument requirements: NanoEnTek FREND™ System
l. Device Description
The FREND™ Free T4 is a rapid fluorescence immunoassay that measures Free T4 in human serum and in lithium heparinized plasma using the FREND™ Free T4 Test System.
The FREND™ Free T4 is a single use fluorescence immunoassay designed to quantify the concentration of free thyroxine in serum and lithium heparinized plasma samples, The FREND™ Free T4 test is a two-step competitive immunoassay with gold nanoparticles labeled with T4-specific monoclonal anti-T4- antibody (mouse), T3-BSA labeled with fluorescent nanoparticles, and fluorescence detection by the FREND™ System.
The FREND™ Free T4 Test utilizes microfluidic technology and detects immunecomplexes bound to Free T4. A 70ul Sample is first incubated during Step 1 for five minutes at 37 degrees C in the Free T4 Gold AB Tube with monoclonal anti-T4 antibody conjugated with gold nanoparticles. In Step 2, 35 ul of the mixture from Step 1 is manually loaded into the inlet of the cartridge, where it hydrates a T3-BSA fluorescent bead conjugate and migrates along the test strip. During migration the bound Free T4 in the sample and the fluorescent bead conjugates of T3-BSA compete to form antigenantibody complex in the test zone. Unbound T3-BSA fluorescent conjugates flow through and bind to the anti-T4 antibody that is fixed on the surface in the reference zone. Step 2 takes approximately four minutes after which the fluorescent signals in the test and reference zones are measured.
Free T4 quantification is based upon the ratio of the intensity of the test and reference zones. A lower ratio of fluorescence is indicative of a higher Free T4 concentration, in other words, the maqnitude of the fluorescence ratio is inversely proportional to the amount of Free T4 in the sample.
The free T4 detection range of the FREND™ Free T4 Test System is 0.4 to 6.0 ng/dL. Results are determined via a lot-specific calibration curve which is generated by the manufacturer using a six-point calibration determined from values averaged from five replicates at each level. The established curve is uploaded to the FREND™ System via the Free T4 Code-chip and is valid until the lot expiration date. The established curve is saved in the code-chip and valid until the expiration date of the test cartridge lot.
The FREND™ Free T4 Test cartridge is a disposable plastic device that houses the reagents and contains a port or opening (inlet) where the sample is applied. Once the sample is applied, it will mix with the reagents and travel towards the detection area via capillary action.
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The FREND™ System is a portable, automated FREND™ cartridge reader. The FREND™ System is based on quantitative immunoassay technology capable of quantifying single or multiple analytes by measuring laser-induced fluorescence in a single-use disposable reagent cartridge. The FREND™ cartridge utilizes micro-fluidics lateral flow technology where the analyte of interest in the sample forms immune complexes while moving through the fluidics pathway in the cartridge. The concentration of the analyte of interest in an unknown sample is calculated using the ratio of the fluorescent intensity of the test zone and the reference zone.
The FREND™ System is a bench top fluorescence reader containing a touch screen user interface. The System has a slot that accepts the FREND™ Free T4 Test Cartridge (which contains the reagents and sample), and is programmed to analyze the Test when the sample has fully reacted with the on-board in-cartridge reagents. Results of the test are displayed on the screen and can be printed on an optional printer.
The FREND™ System software controls the graphical user interface, communication with hardware, database manaqement and data analysis. The software also controls the functions of the mechanical components including the motor, laser, printer control and acquisition of data from the sensor. The user can set the time and date and enter patient ID through the graphic user interface. The user cannot make any changes to the software.
The FREND™ Free T4 Test System includes the following in the kit:
- 20 FREND™ Free T4 cartridges .
- . 20 Gold-T4 antibody tubes
- Disposable pipette tips .
- 1 FREND™ Free T4 Code Chip
- 1 FREND™ Free T4 Package Insert ●
The FREND™ System (previously cleared in K124056 (FREND™ PSA) and K131928 (FREND™ PSA)) is not provided with the kit but is required for the use of the FREND™ Free T4 test cartridge.
J. Substantial Equivalence Information:
A general comparison of the similarities and differences of the assays is presented in the table below:
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| Similarities | |||
|---|---|---|---|
| ltem | FREND™ Free T4 Test System | Abbott ARCHITECT Free T4(K123379) | |
| Intended Use | The FREND™ Free T4 Test Systemis a rapid indirect competitivefluorescence immunoassay for thequantitative determination of freethyroxine (FT4) in human serum andlithium heparinized plasmaspecimens using the FREND™system. Measurements of freethyroxine (FT4) are used in thediagnosis of thyroid disorders. TheFREND™ Free T4 Test System is | The ARCHITECT Free T4 (FT4) is aChemiluminescent MicroparticleImmunoassay (CMIA) for thequantitative determination of freethyroxine (Free T4) in human serumand plasma. The ARCHITECT FreeT4 assay is to be used as an aid inthe assessment of thyroid status.The ARCHITECT Free T4Calibrators are for the calibration of | |
| intended for use in clinicallaboratories. For in vitro diagnosticuse only. The test is not intended foruse in point-of-care facilities. | the ARCHITECT i System whenused for the quantitativedetermination of free thyroxine(FreeT4) in human serum andplasma when using the ARCHITECTFree T4 Reagent Kit.The ARCHITECT Free T4 Controlsare for the verification of theaccuracy and precision of theARCHITECT i System when usedfor the quantitative determination offree thyroxine (Free T4) in humanserum and plasma when using theARCHITECT Free T4 Reagent Kit.For in vitro diagnostic use only. | ||
| Sample Type | Human serum and lithium | Same | |
| heparinized plasma | |||
| AnalyteType of Test | Free thyroxineFluorescent immunoassay | SameChemiluminescent immunoassay | |
| determination of FT4 | determination of FT4 | ||
| Quality Control | Internal procedural/instrument qualitycontrols; External positive andnegative assay controls | Same | |
| Interpretation ofResults | Interpolation from a lot-specificcalibration curve | Same | |
| Measuring Range | 0.40- 6.00 ng/dL | Same | |
| Differences | |||
| Item | FREND™ Free T4 Test System | Abbott ARCHITECT Free T4(K123379) | |
| Sample Size | 70µL for the incubation step and35 µL for the running of the test | 95 µL for the first Free T4 test plus45 µL for each additional Free T4from the same test cup | |
| Test Cartridge | Disposable single-use cartridge | No single-use cartridge | |
| RandomAccess/Degree ofAutomation | No random access, manualmanipulation | Random access, semi-automated |
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K. Performance Characteristics (if/when applicable)
1. Analytical performance:
a. Precision/Reproducibility:
A single lot imprecision study was performed at the NanoEnTek laboratory as described in the CLS/ protocol EP5-A3. Three serum pools with low, intermediate and high Free T4 levels were assayed in duplicate twice per day for 20 days (80 total measurements). The results are summarized below:
| SamplePool | Mean Free T4 Conc.(ng/dL) | Repeatability | Between-run | Between-day | Within-laboratory | ||||
|---|---|---|---|---|---|---|---|---|---|
| SD | CV% | SD | CV% | SD | CV% | SD | CV% | ||
| 1 | 0.917 | 0.067 | 7.3 | 0.000 | 0.0 | 0.032 | 3.5 | 0.074 | 8.1 |
| 2 | 1.850 | 0.103 | 5.6 | 0.000 | 0.0 | 0.069 | 3.7 | 0.124 | 6.7 |
| 3 | 3.979 | 0.186 | 4.7 | 0.152 | 3.8 | 0.093 | 2.3 | 0.258 | 6.5 |
| FREND™ Free T4 Single Site Single Lot Precision | ||
|---|---|---|
| ------------------------------------------------- | -- | -- |
b. Linearity/assay reportable range:
To demonstrate the linearity of the assay, a serum base pool with an elevated free thyroxine (7.5 ng/dL) was diluted to a total of 11 levels according to the dilution protocol outlined in CLSI EP6-A: Evaluation of the Linearity of Quantitative Measurement Procedures: A Statistical Approach. At each dilution level, the samples were measured in duplicate to determine the experimental value of free thyroxine. The FREND™ Free T4 Test System was determined to have acceptable linearity across a free T4 range of 0.11 ~ 7.5 ng/dL, (Slope = 0.978, Intercept = -0.0881, R2 = 0.9938). The measuring range of the FREND™ Free T4 is 0.4 ~ 6 ng/dL, which is within the linearity range.
c. Traceability, Stability, Expected values (controls, calibrators or methods):
The standards/calibrators are internally prepared according to the guideline of CLSI (Clinical Laboratory and Standards Institute), C45-A Measurement of Free Thyroid Hormones; Approved Guideline - first Edition. This internal standard is manufactured by gravimetric methods based on the L-Thyroxine (Sigma T1775, Cell culture grade). At each concentration level, the free T4 levels of calibrators are confirmed by measurement on ARCHITECT i free T4 assay (K123379). There is no need for calibration by the operator as the calibration information is coded in the individual cartridge.
d. Stability
Real-time stability testing for the Free T4 reagent kit was performed according to CLSI EP25-A, Evaluation of Stability of In Vitro Diagnostic Reagent stability studies based on procedures and criteria in the NanoEnTek quality system showed that the cartridges for FREND™ Free T4 are good for at least one year from the date of manufacturer if stored refrigerated appropriately as directed.
e. Detection Limit:
The Limit of Detection (LoD) and Limit of Quantitation (LoQ) for the FREND™ Free T4 were established according to the CLSI EP17-A2 protocol and found to be 0.32 ng/dL, and 0.36 ng/dL, respectively.
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f. Analytical specificity:
Interference Studies
Recovery between 90% to 110% of the expected Free T4, in the presence of interferents, is considered acceptable performance. The interference studies were performed with two levels of free T4 using the recommendations in the CLSI EP07-A2 protocol. Results are summarized in the table below.
| Interferent (Concentration tested) | %RecoveryFree T4 Low | %RecoveryFree T4 High | |
|---|---|---|---|
| Endogenoussubstances | Hemoglobin (500 mg/dL) | 109.5 | 106.3 |
| Bilirubin conjugated (20 mg/dL) | 90.5 | 101.5 | |
| Bilirubin unconjugated (20 mg/dL) | 103.0 | 101.0 | |
| Triglyceride (3 g/dL) | 108.1 | 105.5 | |
| Total protein (12 g/dL) | 107.7 | 103.6 | |
| Biotin (2.5 µ/mL) | 101.5 | 94.0 | |
| IgG (2.5 mg/mL) | 102.9 | 101.7 | |
| IgA (60 µg/mL) | 100.7 | 95.8 | |
| IgM (45 µ/mL) | 106.2 | 94.7 | |
| Pharmaceuticals | Acetaminophen (200 µ/mL) | 104.4 | 100.3 |
| Erythromycin (60 µ/mL) | 102.7 | 100.2 | |
| Diltiazem (6.24 µ/mL) | 109.5 | 91.1 | |
| Verapamil (2 µ/mL) | 108.2 | 90.5 | |
| Acetylcysteine (415 µ/mL) | 102.7 | 109.4 | |
| Acetylsalicylic acid (250 µ/mL) | 96.5 | 98.3 | |
| Amiodarone (6 µ/mL) | 105.0 | 99.1 | |
| Ampicillin-Na (50.3 µ/mL) | 99.7 | 91.8 | |
| Ascorbic acid (60 µ/mL) | 100.0 | 91.9 | |
| Carbimazole (500 ng/mL) | 90.5 | 91.2 | |
| Cefoxitin (66 µ/mL) | 93.5 | 92.7 | |
| Cyclosporine (3 µ/mL) | 103.8 | 96.2 | |
| Doxycycline (30 µ/mL) | 104.8 | 95.1 | |
| Fluocortolone (400 µ/mL) | 90.1 | 99.5 | |
| Furosemide (12.5 µ/mL) | 100.3 | 101.4 | |
| Heparin (3,000 U/L) | 102.2 | 91.2 | |
| Hydrocortisone (1.8 µ/mL) | 96.9 | 90.1 | |
| Ibuprofen (250 µ/mL) | 98.6 | 109.0 | |
| lodide (380 µ/mL) | 98.0 | 86.8 | |
| Levodopa (4 mg/mL) | 99.2 | 103.9 | |
| Methyldopa (15 µ/mL) | 100.0 | 90.0 | |
| Metronidazole (120 µ/mL) | 99.0 | 92.9 | |
| Octreotide (2 ng/mL) | 101.7 | 90.8 | |
| Perchlorate (16 ng/mL) | 99.0 | 91.6 | |
| Prednisolone (3 µ/mL) | 98.6 | 91.6 | |
| Propranolol (2 µ/mL) | 96.9 | 90.0 | |
| Propylthiouracil (10 µ/mL) | 90.5 | 90.8 | |
| Rifampicin (640 µ/mL) | 91.5 | 93.9 | |
| Theophylline (400 µ/mL) | 107.1 | 94.5 | |
| Thiamazole/Methimazole (500 µ/mL) | 102.0 | 90.7 | |
| Avidin (5 µg/mL) | 107.7 | 90.4 | |
| Au-nanoparticles (5 µg/mL) | 103.4 | 97.4 | |
| HeterophilicAntibodies | RF (1075 IU/mL) | 109.2 | 93.5 |
| HAMA (70 ng/mL) | 104.4 | 96.5 |
{9}------------------------------------------------
Cross Reactivity
The following substances were evaluated for potential cross-reactivity with the FREND™ Free T4 at two concentrations. Testing was done according to the CLSI protocol EP07-A2. No significant cross-reactivity was found except for the L-Thyroxine (Levothyroxine) itself.
| Cross-reactant | % Cross-reactivity | |||
|---|---|---|---|---|
| Cross-reactant | Concentration (ng/dL) | Free T4 Low | Free T4 High | |
| Levothyroxine, T4 (1 ug/dL) | 1.000 | 99.44 | 99.57 | |
| Diiodothyronine, T2 (5 ug/dL) | 5.000 | 0.0001 | 0.0006 | |
| Tetraiodothyroacetic Acid (10 ug/dL) | 10,000 | 0.00005 | 0.00005 | |
| Triiodothyroacetic Acid (1 ug/dL) | 1.000 | 0.004 | 0.0157 | |
| Triiodothyropropionic Acid (5 ug/dL) | 5.000 | 0.0019 | 0.0055 | |
| Diiodotyrosine. DIT (1 ug/dL) | 1,000,000 | 1E-06 | 2E-06 | |
| L-Triiodothyronine, T3 (1 ug/dL) | 1.000 | 0.0037 | 0.026 | |
| Monoiodotyrosine (1 ug/dL) | 1,000,000 | 1E-06 | 0.000019 | |
| Reverse T3 (10 ug/dL) | 10.000 | 0.0009 | 0.0022 |
% Cross-reactivity = 100x((Measured value) / interferent concentration), as absolute value
g. Assay cut-off:
Not applicable
2. Comparison studies
a. Method comparison with predicate device:
Comparison studies were performed in a CLIA-certified laboratory testing facility at the time the clinical samples were evaluated. If the predicate device and the FREND™ system could be run at the same time, samples were validated simultaneously using the same aliquot of sample. If that was not practical, two separate aliquots of each sample, freshly defrosted prior to analysis, were used - one for each method. The instrument reagent system used as the predicate device was the Abbott ARCHITECT Free T4 Assay (K123379) run on the Abbott ARCHITECT i System. All samples (358) used in the clinical testing were analyzed by both the predicate and the subject device.
Results generated using the FREND™ Free T4 on the FREND™ System (v) were compared to those obtained using a previously FDA cleared ARCHITECT free T4 assay (x) by Ordinary least square fit method. Results of this study are shown in the table below:
| Slope: 1.010 (95% CI: 0.992 to 1.028) | y-Intercept: 0.057 (95% CI: 0.021 to 0.094) |
|---|---|
| Number of Samples: 358r: 0.986 | Range Tested: 0.43 ~ 5.99 ng/dL |
Comparability using CLSI guideline EP09-A3, shows that the difference between the concentrations measured by the test device and the predicate device is less than the allowable difference and the two methods compare favorably.
b. Matrix comparison:
The matrix comparison study was performed at the NanoEnTek laboratory according to CLSI EP14-A3. Free T4 concentrations in 48 paired serum and lithium heparin samples were measured using the FREND™ Free T4. Passing-Bablok regression analysis of serum results (x) compared to lithium heparin plasma results (y) yielded the following regression, indicating that FREND™ Free T4 can be measured equally well in serum and lithium heparin plasma.
{10}------------------------------------------------
| Slope: 1.017 (95% CI: 0.991 to 1.044) | y-Intercept: -0.008 (95% CI: -0.055 to 0.0451) |
|---|---|
| Number of Samples: 48 | Range Tested: 0.44 ~ 5.63 ng/dL |
-
- 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
-
- Clinical cut-off: Not applicable
5. Expected values/Reference range:
Serum samples from a total of 196 normal, apparently healthy adult individuals were assayed on 3 lots of the FREND™ Free T4 assay using a single FREND™ System. The reference interval for the FREND™ Free T4 Test System, determined according to CLSI C28-A3 guidelines, was found to be 0.83-1.60 ng/dL.
L. Proposed Labeling
The labeling is sufficient and it satisfies the requirements of 21 CFR §809.10.
M. Conclusion
The submitted information in this premarket notification is complete and supports a substantial equivalence determination.
§ 862.1695 Free thyroxine test system.
(a)
Identification. A free thyroxine test system is a device intended to measure free (not protein bound) thyroxine (thyroid hormone) in serum or plasma. Levels of free thyroxine in plasma are thought to reflect the amount of thyroxine hormone available to the cells and may therefore determine the clinical metabolic status of thyroxine. Measurements obtained by this device are used in the diagnosis and treatment of thyroid diseases.(b)
Classification. Class II.