The DensiCHEK™ Plus instrument is intended for use with the VITEK® and VITEK® 2 Systems to measure the optical density of a microorganism suspension. The instrument provides values in McFarland units, proportional to microorganism concentrations. DensiCHEK Plus is indicated for use with polystyrene and glass test tubes and the reading range is 0.0 - 4.0 McFarland. The DensiChek™ Plus has applications as an in vitro diagnostic device.

Device Description

DensiCHEK™ Plus is intended for use with the VITEK® and VITEK® 2 Systems to measure the optical density of a microorganism suspension. The instrument provides values in McFarland units, proportional to microorganism concentrations. The DensiCHEK Plus has applications as an in vitro diagnostic medical device. The DensiCHEK Plus generates a McFarrand value using basic colorimetry, which is a method of measurement that relates the amount of color in a transparent medium (liquid) to the amount of a particular substance in the liquid. The DensiCHEK Plus measures the turbidity of the saline and microorganism suspension using a single wavelength, 580 nm. The absorption of light determines the McFarland value generated by the instrument. The light source in the DensiCHEK plus is an LED that emits a narrow range of wavelengths, and an interference filter is used between the LED and the test tube (sample) to further narrow the wavelength to 580 nm. There are 2 calibration curves pre-programmed into the DensiCHEK Plus, one for glass tubes and one for plastic tubes.

AI/ML Overview

Here's a summary of the acceptance criteria and study information for the DensiCHEK™ Plus as found in the provided document:

The document explicitly states that the DensiCHEK™ Plus demonstrated acceptable accuracy, repeatability (within instrument variability), and reproducibility (between instrument variability) during validation. However, it does not provide a specific table of acceptance criteria or the reported device performance values for these metrics. It only broadly claims "acceptable" performance.

Regarding the predicate device comparison, it states: "DensiCHEK Plus demonstrated substantially equivalent performance when compared with the DensiChek in the performance equivalency study utilizing VITEK 2 Identification and Susceptibility cards and systems." Again, specific numerical results of this equivalency are not provided.

Given the limitations of the provided text, many of the requested details about the study are not available.

1. Table of Acceptance Criteria and Reported Device Performance

Metric	Acceptance Criteria	Reported Device Performance
Accuracy	Not specified (stated as "acceptable")	Not specified (stated as "acceptable during validation")
Repeatability (within instrument variability)	Not specified (stated as "acceptable")	Not specified (stated as "acceptable during validation")
Reproducibility (between instrument variability)	Not specified (stated as "acceptable")	Not specified (stated as "acceptable during validation")
Performance Equivalency to Predicate (DensiChek)	Not specified (implied to be "substantially equivalent")	Not specified (stated as "demonstrated substantially equivalent performance")

2. Sample Size Used for the Test Set and Data Provenance

Sample Size: Not specified.
Data Provenance: Not specified (e.g., country of origin, retrospective/prospective).

3. Number of Experts Used to Establish Ground Truth and Qualifications

This information is not provided. The device measures optical density (McFarland units) and does not inherently rely on expert ground truth in the way a diagnostic imaging device might. Its "ground truth" would likely be based on established physical standards or comparative measurements to a calibrated reference.

4. Adjudication Method for the Test Set

Not applicable/Not specified as the test doesn't involve subjective interpretation that would require adjudication.

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

No, an MRMC study was not done, or at least not described in this document. This type of study is typically relevant for diagnostic devices where human readers interpret output (e.g., medical images). The DensiCHEK Plus is an instrument that provides a direct numerical measurement (McFarland value).

6. Standalone (Algorithm Only) Performance Study

Yes, this entire submission describes the standalone performance of the DensiCHEK Plus. While it mentions use with VITEK and VITEK 2 Systems, the performance validation discussed ("accuracy, repeatability, reproducibility") refers to the DensiCHEK Plus instrument itself and its ability to measure optical density.

7. Type of Ground Truth Used

The ground truth for the DensiCHEK Plus's measurements (McFarland values) would be based on physical standards or calibrated reference methods. The device generates a McFarland value using "basic colorimetry" and compares the absorption of light at 580 nm. The ground truth for this would be the actual, chemically or physically determined turbidity/concentration of microorganism suspensions, or highly accurate reference turbidimeters. The document does not explicitly state how this ground truth was established, but it would involve known standards.

8. Sample Size for the Training Set

Not specified. The document does mention "2 calibration curves pre-programmed into the DensiCHEK Plus, one for glass tubes and one for plastic tubes," implying some form of internal calibration and potentially "training" specific to these tube types, but details are absent.

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

Not explicitly described. For a device like this, the "ground truth" for calibration curves would be established by precisely measuring known concentrations of microbial suspensions (or turbidity standards simulating them) across the specified range, using a highly accurate reference method. This data would then be used to create the specific calibration curves for glass and plastic tubes that equate measured absorbance to McFarland units.

Summary

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510(k) SUMMARY

DensiCHEK™ Plus

510(k) Submission Information:

Submitter's Name:
Address:
Contact Person:

bioMérieux, Inc.

595 Anglum Road Hazelwood, MO 63042

Jolyn Tenllado Associate Staff Regulatory Affairs Specialist

314 -731-8386

314-731-8689

November 26, 2008

B. Device Name:

Formal/Trade Name:

Date of Preparation:

Phone Number:

Fax Number:

Classification Name:

DensiCHEK™ Plus

Fully Automated Short-Term Incubation Cycle Antimicrobial Susceptibility Device, 21 CFR 866. 1645

DensiCHEK Plus Common Name:

C. Predicate Device:

DensiChek (K050002, VITEK 2 Compact)

D. 510(k) Summary:

The DensiCHEK Plus generates a McFarrand value using basic colorimetry, which is a method of measurement that relates the amount of color in a transparent medium (liquid) to the amount of a particular substance in the liquid. In general the concentration of the substance being measured is proportional to the intensity of the solution. The darker the color is, the higher the concentration. Absorbance (Abs) is a commonly used measure of the amount of light absorbed by the solution. Absorbance is given by:

Abs = - log T or Abs = - log (1-10)

Where:

T = Transmittance

I = Intensity of light transmitted through the sample

10 = Intensity of light entering the sample

bioMérieux, Inc.

Fax: 314/731-800/638-4835 595 Anglum Road, Hazelwood, Missouri 63042-2320, USA Phone: 314/731-8500 8700

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The DensiCHEK Plus measures the turbidity of the saline and microorganism suspension using a single wavelength, 580 nm. The absorption of light determines the McFarland value generated by the instrument. The more turbid the suspension is, the higher the McFarland standard measurement. The light source in the DensiCHEK plus is an LED that emits a narrow range of wavelengths, and an interference filter is used between the LED and the test tube (sample) to further narrow the wavelength to 580 nm. There are 2 calibration curves pre-programmed into the DensiCHEK Plus, one for glass tubes and one for plastic tubes. The absorbance is different for glass and plastic, therefore the laboratory technician using the DensiCHEK Plus must choose the appropriate tube type setting for the inoculum suspension based on whether it was prepared in a glass or plastic test tube. The instrument is first zeroed using a test tube filled with saline (blank). The technician then places the well-mixed organism suspension into the instrument and slowly rotates the test tube. The instrument will display a series of dashes followed by a McFarland reading.

DensiCHEK Plus demonstrated substantially equivalent performance when compared with the DensiChek in the performance equivalency study utilizing VITEK 2 Identification and Susceptibility cards and systems. This device also demonstrated acceptable acouracy, repeatability (within instrument variability) and reproducibility (between instrument variability) during validation. The Premarket Notification (510[k]) presents data in support of DensiCHEK Plus.

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DEPARTMENT OF HEALTH & HUMAN SERVICES

Public Health Service

Food and Drug Administration 10903 New Hampshire Avenue Building 66 Silver Spring, MD 20993

Ms. Jolyn Tenllado Associate Director, Regulatory Affairs bioMérieux 595 Anglum Road Hazelwood, MO 63042

Re: K083536

Trade/Device Name: DensiPLUS TM Plus Regulation Number: 21 CFR 866.1645 Regulation Name: Short-Term Antimicrobial Susceptibility Test System Regulatory Class: Class II Product Code: LON Dated: September 9, 2009 Received: September 10, 2009

SFP 1 1 2009

Dear Ms Tenllado:

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. Iisting of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration.

If your device is classified (see above) into class II (Special Controls), 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

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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); and good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820). 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 advice for your device on our labeling regulation (21 CFR Parts 801 and 809), please contact the Office of In Vitro Diagnostic Device Evaluation and Safety at (301) 796-5450. 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 Small Manufacturers, International and Consumer Assistance at its toll-free number (800) 638-2041 or (301) 796-7100 or at its Internet address http://www.fda.gov/cdrh/industry/support/index.html.

Sincerely yours,

Lurdle Kai Poole, MS
for

Sally A. Hojvat, M.Sc., Ph.D. Director Division of Microbiology Devices 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):

Device Name: DensiCHEK™ Plus

Indications For Use:

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)

Freddie L. Cooke

Division Sign-Off

Page 1 of 1

Office of In Vitro Diagnostic Device Evaluation and Safety

sin(k) K083536

K083536 Al p. 91

Regulation Number and Section

§ 866.1645 Fully automated short-term incubation cycle antimicrobial susceptibility system.

(a)
Identification. A fully automated short-term incubation cycle antimicrobial susceptibility system is a device that incorporates concentrations of antimicrobial agents into a system for the purpose of determining in vitro susceptibility of bacterial pathogens isolated from clinical specimens. Test results obtained from short-term (less than 16 hours) incubation are used to determine the antimicrobial agent of choice to treat bacterial diseases.(b)
Classification. Class II (special controls). The special control for this device is FDA's guidance document entitled “Class II Special Controls Guidance Document: Antimicrobial Susceptibility Test (AST) Systems; Guidance for Industry and FDA.”