SEALITE SCIENCES, INC. AQUALITE FREE T, ASSAY

K974551 · Sealite Sciences, Inc. · CEC · Dec 22, 1997 · Clinical Chemistry

Device Facts

• Record ID: K974551
• Device Name: SEALITE SCIENCES, INC. AQUALITE FREE T, ASSAY
• Applicant: Sealite Sciences, Inc.
• Product Code: CEC · Clinical Chemistry
• Decision Date: Dec 22, 1997
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 862.1695
• Device Class: Class 2

Intended Use

The AquaLite® FT4 Bioluminescent Immunoassay (BIA) Kit (or the AquaLite® FT4 Assay) is an in vitro diagnostic product intended for use in the quantitative measurement of FT4 in human serum in clinical laboratories. Free thyroxine measurements are used to diagnosis and treat diseases of the thyroid.

Device Story

AquaLite® Free T4 Assay is a single-site, competitive inhibition bioluminescent immunoassay (BIA) kit. Input: 50 uL human serum sample, calibrators, or controls. Process: Sample pipetted into polystyrene tubes pre-coated with T4 carrier complex; mouse monoclonal anti-T4 antibody linked to AquaLite® added; 90-minute incubation on orbital shaker; wash step removes unbound conjugate. Detection: Luminometer triggers flash-type reaction via calcium buffer injection; AquaLite® oxidizes luciferin to produce light. Output: Light intensity (RLU) measured; signal inhibition inversely proportional to free T4 concentration. Calculation: Cubic spline curve fit applied to log-log transformation of RLU vs. concentration. Used in clinical laboratories by technicians/lab personnel. Results assist clinicians in diagnosing and managing thyroid disease.

Clinical Evidence

Bench testing only. Performance evaluated via sensitivity (0.007 ng/dL), intra-assay precision (2.9-10.1% CV), and inter-assay precision (3.4-13.0% CV). Method comparison (n=127) against a commercial chemiluminescence assay showed a correlation coefficient of 0.92, slope 1.1, and y-intercept -0.2. Interference testing confirmed no significant impact from hemoglobin, albumin, oleic acid, bilirubin, salicylate, or phenylbutazone at tested levels. Kinetics studies confirmed 90-minute incubation as optimal.

Technological Characteristics

Competitive inhibition bioluminescent immunoassay. Solid phase: polystyrene tubes pre-coated with T4 carrier complex. Conjugate: mouse monoclonal anti-T4 antibody linked to AquaLite®. Detection: luminometer-based flash-type reaction triggered by calcium buffer. Software: cubic spline curve fit algorithm. Sample type: serum/plasma. Sterilization: not specified.

Indications for Use

Indicated for the quantitative measurement of free thyroxine (FT4) in human serum to aid in the diagnosis and treatment of thyroid diseases in clinical laboratory settings.

Regulatory Classification

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.

Predicate Devices

• Nichols Institute Free T4 Assay

Submission Summary (Full Text)

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K974551

DEC 2 2 1997

SeaLite Sciences, Inc.

# 510(k) SUMMARY

#### I. GENERAL INFORMATION

Trade or proprietary name - SeaLite Sciences, Inc. AquaLite® Free T, Assay

Common or usual name - Bioluminescent immunoassay (BIA)

Classification name - FDA has classified Free To test systems intended for the measurement of free thyroxine in serum or plasma to diagnose and treat diseases of the thyroid as Class II devices. (21 C.F.R. § 862.1695)

| Submitter's Name | Cathryn N. Cambria, Director |
|------------------|------------------------------------------|
| and Address: | Regulatory Affairs and Quality Assurance |
| | SeaLite Sciences, Inc. |
| | 3000 Northwoods Parkway |
| | Suite 200 |
| | Norcross, GA 30071 |
| | [phone], ext. 227 |
| Submission Date: | December 3, 1997 |

Legally Marketed Device To Which Claim Substantial Equivalence:

Nichols Institute Free T4 Assay

### II. INDICATIONS FOR USE

The AquaLite® Free T Bioluminescent Immunoassay (BIA) Kit (or the AquaLite® Free T . Assay) is an in vitro diagnostic product intended for use in clinical laboratories for the quantitative determination of human free T4 in serum.

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## III. DEVICE DESCRIPTION

The AquaLite® Free T. Assay is a single-site, competitive inhibition bioluminescent immunoassay kit. A T carrier complex is immobilized on polystyrene tubes (solid phase). Serum samples, appropriate calibrators or controls, are pipetted (50 uL) into the pre-coated tubes. A mouse monoclonal anti-T antibody covalently linked to AquaLite® (100 uL) is then added to the tubes. Free T. in the sample competes with immobilized T for the available T binding sites of the anti-T antibody conjugate. Complex formation is complete after a 90-minute incubation period at room temperature 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 presence of Ta in the sample or calibrator reduces the binding of the conjugate to the immobilized T . pre-coated on the tubes. The amount of signal inhibition is indirectly proportional to the Free T concentration. To calculate results, the luminometer uses a cubic spline curve fit applied to a log-log transformation of the light intensity (in relative light units, RLU) of the Free T calibrators versus Free T, concentration (in ng/dL).

## SUMMARY OF STUDIES AND TECHNOLOGICAL CHARACTERISTICS IV.

Studies on the AquaLite® Free T. Assay were conducted at SeaLite Sciences. The results are summarized below:

# Performance Characteristics

### 1. Sensitivity

The sensitivity or detection limit of the AquaLite® Free T. Assay is 0.007 ng/dL. Sensitivity is calculated by determining the Free Ta concentration that corresponds to the 95% confidence level of twenty replicates of the A Calibrator (0 ng/dL).

### 2. Specificity and Cross Reactivity

Cross reactivity of the AquaLite® Free T Assay was determined by spiking Calibrator A containing Free Ta (0 ng/dL) with the following compounds.

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| Compound | Concentration | % Cross Reactivity |
|-------------------------|---------------|--------------------|
| Triiodo-L-thyronine | 20 µg/dL | undetectable |
| Triiodothyroacetic acid | 20 µg/dL | undetectable |
| Monoiodotyrosine | 20 µg/dL | undetectable |
| Diiodo-L-tyrosine | 20 µg/dL | undetectable |
| Methimazole | 0.4 mg/mL | undetectable |
| 6-n-Propyl-2-thiouracil | 0.4 mg/mL | undetectable |

## 3. Drift

Two patient samples were run (5 duplicates each) and assayed for reagent addition drift. The data demonstrate that the AquaLite® Free T. Assay does not exhibit "end of run" effect with 100 tubes.

| | (All measurements, in ng/dL) | | |
|--------|------------------------------|-------|--------|
| | Tubes | Tubes | Tubes |
| Sample | 20-30 | 50-60 | 90-100 |
| 1 | 2.8 | 2.9 | 2.8 |
| 2 | 4.5 | 4.5 | 4.5 |

### Precision and Reproducibility 4.

- Intra-assay precision. Three serum controls containing Free T4 at the a. following concentrations were assayed to determine intra-assay precision (n=20 per concentration level).

| Free T4 Level (ng/dL) | % CV |
|-----------------------|------|
| 0.75 | 10.1 |
| 2.6 | 4.1 |
| 4.4 | 2.9 |

- Inter-assay precision. Three serum controls containing Free T4 at the b. following concentrations were assayed in duplicate in 20 assays. A new standard curve was generated for each assay (n = 2 x 20 = 40). Inter-assay precision observed over a 2 week period for the solutions is as follows:

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| Free T4 Level (ng/dL) | % CV |
|-----------------------|------|
| 0.6 | 13.0 |
| 2.6 | 5.0 |
| 4.2 | 3.4 |

#### 5. Method Comparison

Free Tg ranging from 0.27 to 3.67 ng/dL in serum samples (n = 127) was measured using the AquaLite® Free T Assay and a commercially available chemiluminescence immunometric assay kit for Free T4. Correlation by linear regression analysis gave a slope of 1.1 with a y intercept of -0.2. The correlation coefficient was 0.92.

# 6. Kinetics

Three human serum samples were assayed in parallel at 60 minutes, 90 minutes and 120 minutes to demonstrate the effect of incubation times. Results indicate a 90 minute incubation is optimal.

| Standard<br>ng/dL | 1 Hour<br>%B/Bo | 1.5 Hours<br>%B/Bo | 2 Hours<br>%B/Bo |
|-------------------|-----------------|--------------------|------------------|
| 0 | 100.0 | 100.0 | 100.0 |
| 0.4 | 85.9 | 84.0 | 82.6 |
| 0.9 | 68.8 | 68.1 | 68.8 |
| 2 | 38.0 | 38.4 | 41.2 |
| 4 | 8.6 | 9.1 | 10.7 |

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| Sample<br>ng/dL | Free T4<br>ng/dL | Free T4<br>ng/dL | Free T4<br>ng/dL |
|-----------------|------------------|------------------|------------------|
| 1 | 0.6 | 0.6 | 0.5 |
| 2 | 2.6 | 2.6 | 2.7 |
| 3 | 4.4 | 4.4 | 4.4 |

# 7. Recovery in Serum and Plasma

Blood samples from 7 normal subjects were prepared as sera (standard technique and SST tubes) as well as heparin and EDTA plasmas. Free T, was quantified using the AquaLite® Free T , Assay . Recovered Free T , was compared with the Free T , recovered in serum (standard technique). The data demonstrates that there are no significant differences between standard serum or serum separator tubes, nor heparin and EDTA plasmas when using the AquaLite® Free T4 Assay.

| Sample | Serum | Heparin | EDTA | SST |
|--------|-------|---------|------|-----|
| 1 | 1.5 | 1.4 | 1.4 | 1.3 |
| 2 | 1.5 | 1.6 | 1.5 | 1.4 |
| 3 | 1.6 | 1.8 | 1.5 | 1.4 |
| 4 | 1.8 | 1.7 | 1.8 | 1.6 |
| 5 | 1.4 | 1.4 | 1.4 | 1.3 |
| 6 | 1.3 | 1.3 | 1.5 | 1.2 |
| 7 | 0.9 | 1.0 | 0.8 | 0.6 |

# 8. Effect of Hemolysis

Three patient samples were spiked with preparations of hemoglobin and assayed to demonstrate effect of mild, moderate and severely hemolyzed serum. The data demonstrates that the AquaLite® Free T. Assay is not significantly affected by hemoglobin.

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| Sample | Neat | Mild | Moderate | Severe |
|--------|------|------|----------|--------|
| 1 | 1.6 | 1.5 | 1.5 | 1.5 |
| 2 | 1.7 | 1.5 | 1.8 | 1.7 |
| 3 | 1.0 | 1.1 | 0.9 | 1.1 |

### 9. Effect of TBG

This experiment tested for the possible interference of the immobilized Free T with purified TBG. If TBG bound to the immobilized Free T., there would be a reduction of binding of the anti-T. AquaLite® Free T. conjugate. This would be reflected in an apparent increase in Free T concentration. At a normal TBG level (15-34 mg/L)18 there was no interference of the AquaLite® Free T4 Assay. There was slight inhibition of the %B/Bo at 200 and 300 mg/L of TBG (5.9 and 8.8 times normal physiologic level).

| TBG Added | %B/Bo |
|-----------|-------|
| 0 | 100% |
| 50 mg/L | 100 % |
| 75 mg/L | 100% |
| 100 mg/L | 104% |
| 200 mg/L | 91% |
| 300 mg/L | 93% |
| 600 mg/L | 73% |

### 10. Effect of Albumin

Three patient samples were spiked with 15, 25 and 75 mg/mL of albumin and assayed. The data demonstrate that the AquaLite® Free T4 Assay is not significantly affected by albumin.

| Sample | Neat | Albumin | | |
|--------|------|----------|----------|----------|
| | | 15 mg/mL | 25 mg/mL | 75 mg/mL |
| 1 | 1.8 | 1.6 | 1.5 | 1.9 |
| 2 | 1.2 | 1.3 | 1.2 | 1.4 |
| 3 | 1.3 | 1.4 | 1.3 | 1.6 |

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### 11. Effect of Nonesterified Fatty Acids

Three patient samples were spiked with 2.5, 5 and 10 mmol/L oleic acid and assayed. The data demonstrate that the AquaLite® Free F4 Assay is not significantly affected by oleic acid at the levels tested.

| Sample | Neat | 2.5 mmol/L | 5 mmol/L | 10 mmol/L |
|--------|------|------------|----------|-----------|
| 1 | 0.9 | 0.9 | 1.2 | 1.0 |
| 2 | 1.5 | 1.5 | 1.4 | 1.4 |
| 3 | 1.1 | 0.9 | 1.1 | 1.1 |

### 12. Effect of Bilirubin

Three patient samples were spiked with 10 and 20 mg/dL bilirubin and assayed. The data demonstrate that the AquaLite® Free T Assay is not significantly affected by bilirubin at the levels tested.

| Sample | Neat | Bilirubin | |
|--------|------|-----------|----------|
| 1 | 1.1 | 10 mg/dL | 20 mg/dL |
| 1 | 1.1 | 1.3 | 1.2 |
| 2 | 1.1 | 1.0 | 1.0 |
| 3 | 1.5 | 1.4 | 1.3 |

### 13. Effect of Salicylate

Three patient samples were spiked with 1, 5, 10 and 25 mg/dL salicylate and assayed. The data demonstrate that the AquaLite® Free T Assay is not significantly affected by salicylate at the levels tested.

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| | | Salicylate | | | |
|--------|------|------------|---------|----------|----------|
| Sample | Neat | 1 mg/dL | 5 mg/dL | 10 mg/dL | 25 mg/dL |
| 1 | 1.5 | 1.3 | 1.7 | 1.7 | 1.6 |
| 2 | 0.9 | 1.2 | 0.8 | 1.1 | 1.1 |
| 3 | 0.9 | 1.0 | 1.2 | 0.9 | 1.2 |

### 14. Effect of Phenytoin

Two patient samples were spiked with 1, 5, 10 and 25 µg/mL phenytoin and assayed. The data demonstrate that the AquaLite® Free T. Assay is not significantly affected by phenytoin at the I to 11 1100ay is needing to patients falling
Should be interpreted with courtion.

| | Phenytoin | | | | |
|--------|-----------|--------|--------|---------|---------|
| Sample | Neat | 1µg/mL | 5µg/mL | 10µg/mL | 25µg/mL |
| 1 | 1.1 | 1.0 | 1.6 | 1.6 | 2.2 |
| 2 | 1.5 | 1.2 | 1.5 | 1.9 | 2.2 |

#### 15. Effect of Phenylbutazone

Three patient samples were spiked with 1, 5 and 10 ug/mL phenylbutazone and assayed. The data demonstrate that the AquaLite® Free T. Assay is not significantly affected by phenylbutazone at the levels tested.

| Sample | Neat | 1 µg/mL | 5 µg/mL | 10 µg/mL |
|--------|------|---------|---------|----------|
| 1 | 1.0 | 1.0 | 0.9 | 0.8 |
| 2 | 1.7 | 1.6 | 1.4 | 1.7 |
| 3 | 0.9 | 0.7 | 0.8 | 0.8 |

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### POTENTIAL ADVERSE EFFECTS OF THE DEVICE ON HEALTH V.

Use Universal Precautions. No known test method can offer complete Caution: 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 demonstrate that the performance of SeaLite Sciences, Inc. AquaLite® Free T Assay is similar and substantially equivalent to that of other commercially available assays for Free T4.

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Image /page/9/Picture/1 description: The image shows the logo for the U.S. Department of Health & Human Services. The logo features a stylized depiction of an eagle or bird-like figure with three curved lines representing its body and wings. The text "DEPARTMENT OF HEALTH & HUMAN SERVICES - USA" is arranged in a circular pattern around the bird symbol.

Food and Drug Administration 2098 Gaither Road Rockville MD 20850

DEC 22 1997

Cathryn Cambria · Director, Regulatory Affairs and Quality Assurance SeaLite Sciences, Inc. 3000 Northwoods Parkway, Suite 200 Norcross, Georgia 30071

Re : K974551 AquaLite® Free T4 Assay r Requlatory Class: II Product Code: CEC December 3, 1997 Dated: Received: December 4, 1997

Dear Ms. Cambria:

We have reviewed your Section 510(k) notification of intent to market the device referenced above and we have determined the market is substantially equivalent (for the indications for use stated in the enclosure) to 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). You may, therefore, market the device, subject to the general controls provisions The general controls provisions of the Act 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 (Premarket Approval), it may be subject to such additional controls. Existing major regulations affecting your device can be found in the Code of Federal Requlations, Title 21, Parts 800 to 895. A substantially equivalent determination assumes compliance with the Current Good Manufacturing Practice requirements, as set forth in the Quality System Regulation (QS) for Medical Devices: General regulation (21 CFR Part 820) and that, through periodic QS inspections, the Food and Drug Administration (FDA) will verify such assumptions. Failure to comply with the GMP regulation may result in regulatory action. In addition, FDA may publish further announcements concerning your device in the Federal Register. Please note:

this response to your premarket notification submission does not affect any obligation you might have under sections 531 through 542 of the Act for devices under the Electronic Product Radiation Control provisions, or other Federal laws or requlations.

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Page 2

Under the Clinical Laboratory Improvement Amendments of 1988 (CLIA-88), this device may require a CLIA complexity categorization. To determine if it does, you should contact the Centers for Disease Control and Prevention (CDC) at [phone].

This letter will allow you to begin marketing your device as The FDA described in your 510 (k) premarket notification. 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 advice for your device on our labeling regulation (21 CFR Part 801 and additionally 809.10 for in vitro diagnostic devices), please contact the Office of Compliance at [phone]. Additionally, for questions on the promotion and advertising of your device, please contact the Office of Compliance at [phone]. Also, please note the regulation entitled, "Misbranding by reference to
premarket notification" (21 CFR 807.97). Other general information on your responsibilities under the Act may be obtained from the Division of Small Manufacturers Assistance at its toll-free number [phone] or [phone] or at its internet address "http://www.fda.gov/cdrh/dsmamain.html".

Sincerely yours,
Steven Litman

Steven I. Gutman, M.D., M.B.A. Director Division of Clinical Laboratory Devices Office of Device Evaluation Center for Devices and Radiological Health

Enclosure

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Page _ 1 of _1

510(k) Number (if known): K974551

Device Name: AquaLite® FT4 Bioluminescent Immunoassay (BIA) Kit (or the AquaLite® FT4 92284

Indications for Use:

The AquaLite® FT4 Bioluminescent Immunoassay (BIA) Kit (or the AquaLite® F14 Assay) is an in vitro diagnostic product intended for use in the quantitative measurement of FT4 in human serum in clinical laboratories. Free thyroxine measurements are used to diagnosis and treat diseases of the thyroid.

V. Michell Charles for Abe Montgomery

(Division Sign-Off)
Division of Clinical Laboratory Levices
510(k) Number 6974501

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

Concurrence of CDRH, Office of Device Evaluation (ODE)

Prescription Use _

OR

Over-The-Counter Use _________________________________________________________________________________________________________________________________________________________

(Per 21 CFR 801.109)

(Optional Format 1-2-96)