DIAZYME POTASSIUM ENZYMATIC ASSAY KIT

K042191 · Diazyme Laboratories · MZV · Oct 29, 2004 · Clinical Chemistry

Device Facts

• Record ID: K042191
• Device Name: DIAZYME POTASSIUM ENZYMATIC ASSAY KIT
• Applicant: Diazyme Laboratories
• Product Code: MZV · Clinical Chemistry
• Decision Date: Oct 29, 2004
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 862.1600
• Device Class: Class 2

Intended 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.

Device Story

Spectrophotometric enzymatic assay for quantitative determination of potassium ions in human serum. Reagents (diluent 1/enzyme 1 and diluent 2/substrate 2) mixed with serum sample; incubated at 37 °C. Absorbance measured at 450 nm at 3 and 5 minutes. Uses bi-level serum calibrators (3 mM and 7 mM) to generate linear calibration curve. Controls (normal 4.4 mM, abnormal 6.4 mM) verify assay functionality. Performed manually or on automated chemistry analyzers. Output is potassium concentration (mmol/L) used by clinicians to assess patient electrolyte status.

Clinical Evidence

Bench testing only. Performance evaluated via correlation study with the predicate device (r=0.96). Analytical recovery averaged 104% and 97% for spiked serum samples. Precision and linearity were assessed. Interference studies conducted for various substances (e.g., NH4Cl, NaPi, CaCl2, NaCl, CuCl2, ZnCl2, FeCl3, Ascorbic Acid, Glucose, Bilirubin) showed minimal interference at tested concentrations.

Technological Characteristics

Two-reagent (R1 and R2) kinetic assay system. Principle: Spectrophotometric measurement at 450 nm. Measuring range: 2 to 8 mmol/L. Compatible with automated clinical analyzers. No software algorithm class specified; relies on standard spectrophotometric absorbance quantification.

Indications for Use

Indicated for quantitative determination of potassium in human serum for prescription use.

Regulatory Classification

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.

Predicate Devices

• Synchron LX I 725 Clinical System (K023049)

Submission Summary (Full Text)

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K042191

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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: [phone] Fax: [phone]

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.

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

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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 [phone]. 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 [phone] or [phone] 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