Diazyme Potassium Enzymatic Assay Kit in conjunction with Diazyme Potassium Low and High Calibrators, are intended for the quantitative determination of Potassium (K) in serum.

Device Description

Potassium is determined spectrophotometrically through a kinetic coupling assay system using potassium dependent urea amidolyase (UAL). NADH generated in a coupling enzymatic reaction reduces a water soluble colorless tetrazolium salt, WST-1 in the presence of an electron mediator, 1-methoxy-5-methyl-phenazinium methyl sulfate (PMS), to form a water soluble formazan dye, which has a maximum absorbance at 450 nm. The corresponding increase of optical density at 450 nm is proportional to the potassium concentration in the serum. Diazyme's Potassium Enzymatic Assay is a two reagent (R1 and R2) based kinetic assay system. The results are obtained in 15 min by measuring absorbance at 450 nm. No off line pretreatment is needed. The assay has a wide measuring range from 2 to 8 mmol/L of serum potassium.

AI/ML Overview

Here's an analysis of the acceptance criteria and study detailed in the provided 510(k) submission, formatted as requested:

1. Table of Acceptance Criteria and Reported Device Performance

The acceptance criteria are implicitly derived from the comparison with the predicate device and the general understanding of what constitutes a "good correlation," "excellent precision," and "little interference" for an in vitro diagnostic device of this type. Specific numerical targets for correlation or precision are not explicitly stated as "acceptance criteria" but are demonstrated through the study results.

Performance Metric	Acceptance Criteria (Implicit/Demonstrated)	Reported Device Performance
Correlation	Good correlation with predicate device	Correlation coefficient of 0.96 with Synchron LX I 725 Clinical System
Analytical Recovery	Expected recovery for spiked samples	104% and 97% for potassium added to two different sera
Precision	Excellent precision	Data presented in an unreadable table, preventing extractable numerical values.
Interference	Little interference from common substances	Little interference at specified concentrations for NH4Cl, NaPi, CaCl2, NaCl, CuCl2, ZnCl2, FeCl3, Ascorbic Acid, Glucose, Bilirubin

2. Sample Size for the Test Set and Data Provenance

Test Set Sample Size: The document mentions "clinical patient serum samples" were used for comparison analysis but does not specify the exact number of samples in the test set.
Data Provenance: The document does not explicitly state the country of origin of the data. It implies retrospective data as it refers to comparing results with a legally marketed predicate device on patient samples, but does not explicitly state if it was retrospective or prospective.

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

This information is not provided in the document. For in vitro diagnostic assays measuring an analyte like potassium, the "ground truth" is typically established by the results from a recognized reference method or a legally marketed predicate device, as opposed to expert human interpretation.

4. Adjudication Method for the Test Set

This information is not applicable and therefore not provided. As explained in point 3, the "ground truth" for this type of device is an objective measurement rather than a subjective interpretation requiring adjudication among experts.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

An MRMC comparative effectiveness study was not conducted and is not applicable for this type of in vitro diagnostic device. This study design is typically used for imaging or diagnostic devices where human readers interpret results, and the AI assists in that interpretation. This device is an automated enzymatic assay.

6. Standalone Performance Study

Yes, a standalone performance study was done. The document describes several performance characteristics of the Diazyme Potassium Enzymatic Assay itself, including:

Precision: Stated as "excellent precision" with a table (though unreadable).
Measuring Range: 2 to 8 mmol/L.
Analytical Recovery: Demonstrated with spiked samples.
Interference Study: Tested against various common substances.
Correlation: Compared to the predicate Synchron LX I 725 Clinical System using clinical patient serum samples.

This comprehensive characterization of the Diazyme device's performance, independently and in comparison to a predicate, constitutes a standalone performance study.

7. Type of Ground Truth Used

The ground truth for the test set (clinical patient serum samples) was established by comparison with a legally marketed predicate device (Synchron LX I 725 Clinical System), which itself would have been validated against established reference methods or clinical outcomes. The document also refers to a "comparison analysis" with the predicate, indicating the predicate's results served as the reference for evaluating the new device's accuracy.

8. Sample Size for the Training Set

The document does not provide information about a separate "training set" or its sample size. This is typical for an enzymatic assay, where the assay reagents and parameters are developed and optimized through laboratory work and internal validation rather than machine learning on a distinct training dataset.

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

Since no distinct "training set" for an algorithm is mentioned or implied, the concept of establishing ground truth for a training set is not applicable. The "ground truth" in the development of such assays refers to the accurate measurement of potassium in known samples (e.g., calibrators, controls, or reference materials) that are used to develop and optimize the assay's chemical and enzymatic reactions and calibration curves.

Summary

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K042191

Image /page/0/Picture/2 description: The image shows the word "DIAZYME" in bold, block letters. Above the word is a four-pointed star-like symbol. The symbol is black and has a slightly gothic appearance. The overall image is simple and clear, with a focus on the text and the symbol.

OCT 2 9 2004

Summary

Submitter's name:

Submitter's address:

Phone: Fax: Name of Contact Person: 3550 General Atomics Court San Diego, CA 92121 858-455-4761 858-455-4750 Huan Tran Diazyme Laboratories Division General Atomics 3550 General Atomics Court San Diego. CA 92121 Phone: 858-455-4761 Fax: 858-455-4750

Diazyme Laboratories Division, General Atomics

Date the summarv was prepared: August 9, 2004

Name of the device:	Potassium Enzymatic Assay
Trade Name:	Diazyme Potassium Enzymatic Assay
Common/Usual Name:	Enzymatic Assay, Potassium
Classification Name:	Electrode, Ion Specific, Potassium
Device Class:	II

Predicate Device:

The legally marketed device to which we are claiming equivalence [807.92(a)(3)]: Synchron LX I 725 Clinical System (K023049) manufactured by Beckman Coulter Inc., Brea, CA, USA.

Description of the devices

In healthy individual, an extracellular fluid level of potassium is regulated to maintain at 3.5-5.5mM. Small deviations from normal level can have severe health consequences. Monitoring serum potassium concentration is important in both routine check and emergency rooms. Currently, the two most commonly used methods to detect serum potassium are ion-selective electrode (ISE) and flame photometry. However, routine maintenance of these analyzers requires much effort and sometimes would be cumbersome. Diazyme's Potassium Enzymatic assay is proven to be equivalent to ISE method but more user friendly in automated analyzers.

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mediator, 1-methoxy-5-methyl-phenazinium methyl sulfate (PMS), to form a water soluble formazan dye, which has a maximum absorbance at 450 nm. The corresponding increase of optical density at 450 nm is proportional to the potassium concentration in the serum

Intended Use of the Device:

Diazyme Potassium Enzymatic Assay Kit in conjunction with Diazyme Potassium Low and High Calibrators, are intended for the quantitative determination of Potassium (K) in serum.

Performance Characteristics

Diazyme's Potassium Enzymatic Assay is a two reagent (R1 and R2) based kinetic assay system. The results are obtained in 15 min by measuring absorbance at 450 nm. No off line pretreatment is needed. The assay has a wide measuring range from 2 to 8 mmol/L of serum potassium. The assay offers excellent precision as shown in the table below:

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Diazyme's Potassium Enzymatic assay has a good correlation with Synchron LX 1 725 Clinical System with a correlation coefficient of 0.96. The average analytical recoveries for potassium added to two different sera were 104% and 97% respectively. We have conducted interference study by spiking the substances to be tested to the pooled human sera and found little interference at the indicated concentrations:

Interference	Concentration
NH4Cl	1 mM
NaPi	1.5 mM
CaCl2	5 mM
NaCl	200 mM
CuCl2	0.25 mM
ZnCl2	0.25 mM
FeCl3	0.025 mM
Ascorbic Acid	5 mM
Glucose	5 mM
Bilirubin	10mg/dl

Conclusion: Comparison analysis presented in the 510K submission for this device in the comparison section, together with linearity, precision and interference study presented demonstrated that the Diazyme's Potassium Enzymatic Assay has excellent accuracy and is safe and effective. There is no significant deviation between the results obtained by Diazyme's Potassium Enzymatic Assay and legally marketed predicate when testing clinical patient serum

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samples Therefore, Diazyme's Potassium Enzymatic Assay is substantially similar to the commercially available products to measure potassium levels in human serum samples.

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Image /page/3/Picture/1 description: The image shows the logo for the U.S. Department of Health & Human Services. The logo features a stylized caduceus symbol, which is often associated with medicine and healthcare. The caduceus is composed of three curved lines that resemble a stylized staff with snakes intertwined around it. The text "DEPARTMENT OF HEALTH & HUMAN SERVICES • USA" is arranged in a circular pattern around the caduceus symbol.

OCT 2 9 2004

Food and Drug Administration 2098 Gaither Road Rockville MD 20850

Mr. Huan Tran Quality Assurance Manager Diazyme Laboratories Division of General Atomics 3550 General Atomics Court San Diego, CA 92121

K042191 Re:

Trade/Device Name: Diazyme Potassium Enzymatic Assay Kit Diazyme Enzymatic Potassium Serum Controls Regulation Number: 21 CFR 862.1600 Regulation Name: Potassium test system Regulatory Class: Class II Product Code: MZV, JJX Dated: August 9, 2004 Received: August 12, 2004

Dear Mr. Tran:

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

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

Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21

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

If you desire specific information about the application of labeling requirements to your device, or questions on the promotion and advertising of your device, please contact the Office of In Vitro Diagnostic Device Evaluation and Safety at (301) 594-3084. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21CFR Part 807.97). You may obtain other general information on your responsibilities under the Act from the Division of Small Manufacturers, International and Consumer Assistance at its toll-free number (800) 638-2041 or (301) 443-6597 or at its Internet address http://www.fda.gov/cdrh/dsma/dsmamain.html.

Sincerely yours,

Jean M. Cooper, US, Div.

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

Enclosure

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Indications for Use

510(k) Number (if known): K042191

Device Name: Diazyme Potassium Enzymatic Assay Kit

Indications for Use:

Diazyme Potassium Enzymatic Assay Kit in conjunction with Diazyme Potassium Low and High Calibrators, are intended for the quantitative determination of sodium (K) in serum.

Diazyme Potassium Enzymatic Assay Kit contains a low level standard and a high level standard. The standards are used to generate a linear graph that will be used in the calculation of potassium concentrations in unknown serum samples.

Diazyme Potassium Enzymatic Assay has controls for normal serum potassium level and abnormal serum potassium level. The controls are used as reference samples for checking the functionality of the Diazyme Potassium Enzymatic Assay.

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

Over-The-Counter Use (21 CFR 807 Subpart C)

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

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

Albert Cuti'
Division Sign-Off

Office of In Vitro Diagnostic

510(k) K042191

Regulation Number and Section

§ 862.1600 Potassium test system.

(a)
Identification. A potassium test system is a device intended to measure potassium in serum, plasma, and urine. Measurements obtained by this device are used to monitor electrolyte balance in the diagnosis and treatment of diseases conditions characterized by low or high blood potassium levels.(b)
Classification. Class II.