The Visby Medical Sexual Health Test is a single-use (disposable), fully-integrated, automated Polymerase Chain Reaction (PCR) in vitro diagnostic test intended for use in point-of-care or clinical laboratory settings for the rapid detection and differentiation of DNA from Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis in self-collected female vaginal swab specimens using the Visby Medical Sexual Health Vaginal Specimen Collection Kit in a health care setting. The test results are to aid in the diagnosis of symptomatic infections with Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis.

Device Description

The Visby Medical Sexual Health Test (Visby Test) is a single-use (disposable), fully integrated, rapid, compact device containing a PCR-based assay for direct qualitative detection and differentiation of DNA from CT, NG, and TV. The test system includes the Visby Medical Sexual Health device, the Visby Medical power supply, the Visby Medical Vaginal Specimen Collection kit, and fixed-volume transfer pipettes. The device processes self-collected vaginal swab samples by automatically performing all steps required to complete lysis, polymerase chain reaction, and amplicon detection.

The patient uses the Visby Medical Vaginal Specimen Collection Kit to self-collect a vaginal specimen with the provided flocked swab, and then the patient elutes the specimen into the Visby Medical Collection Media. The test operator transfers the collection media containing the patient specimen into the sample port of the device using the provided fixed-volume pipette where it rehydrates a lyophilized internal process control. The sample enters a lysis module, where the DNA of the sample and the internal process control are extracted using a combination of chemical lysis and high temperature. The extracted DNA enters a mixing chamber where it rehydrates lyophilized PCR reagents, followed by thermocycling to amplify target DNA. If present, the amplified pathogen target (CT, NG, and/or TV) and internal process control hybridize to specific probes located on a flow channel. Detection of the target-specific PCR product is accomplished via an enzyme-linked colorimetric assay using streptavidin bound horseradish peroxidase (HRP) and a colorimetric substrate that forms a purple precipitate. Test results can be expected in approximately 30 minutes: a green check mark will appear, and a purple color will appear in the "Results Valid" spot, indicating a valid test. A purple spot adjacent to "Chlamydia," "Gonorrhea," and/or "Trichomoniasis" signifies the presence of amplified CT, NG, and/or TV DNA in the sample.

Vaginal self-collection kits containing a tube of collection media compatible with the Sexual Health test and a collection swab are also packaged separately. External controls recommended in the product labeling are commercially available from a different manufacturer.

AI/ML Overview

Here's a breakdown of the acceptance criteria and study information based on the provided document:

1. Table of Acceptance Criteria and Reported Device Performance

The document does not explicitly state formal acceptance criteria in terms of specific PPA/NPA thresholds for substantial equivalence to the predicate device. Instead, the studies presented aim to demonstrate "comparability" or "equivalence" to the predicate device (Visby Medical Sexual Health Click Test, K200748/CW200003). Therefore, the reported performance is compared directly against the predicate where applicable.

Based on the "Clinical Performance of the Visby Test compared to the Click test performed by untrained operators" (Table 3) and "Performance of Visby Test Compared to Click Test - Clinical Specimens" (Table 4), the reported device performance is:

Target	Performance Metric	Untrained Operators (Table 3)	Trained Operators (Table 4)
Chlamydia trachomatis (CT)	PPA (95% CI)	100.0% (88.6%-100.0%)	100.0% (96.8% - 100.0%)
	NPA (95% CI)	100% (94.9%-100.0%)	98.7% (96.3% - 99.6%)
Neisseria gonorrhoeae (NG)	PPA (95% CI)	100.0% (83.9%-100.0%)	100.0% (89.9% - 100.0%)
	NPA (95% CI)	100.0% (95.5%-100.0%)	100.0% (98.8% - 100.0%)
Trichomonas vaginalis (TV)	PPA (95% CI)	100.0% (88.6%-100.0%)	93.5% (87.1% - 96.8%)
	NPA (95% CI)	95.8% (88.3%-98.6%)	98.4% (95.9% - 99.4%)

Note: The acceptance criteria for the LoD comparison was explicitly stated: "The LoD values were determined to be equivalent if the lowest concentrations of organism with at least 19/20 detection rate from the two devices were within 3-fold of each other." As seen in Table 1, this criterion was met for all organisms.

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

LoD Comparison: Not explicitly stated as a "test set" in the traditional sense for PPA/NPA. For each LoD multiple, 20 Visby devices and 20 Click devices were tested. The data provenance appears to be laboratory-generated (spiked samples in negative pooled clinical vaginal sample).
Reproducibility Study: Seven (7) panel members (negative, low positive, moderate positive for CT, NG, TV) were used. Each panel member was tested by 6 operators (2 per site) three times each day over 6 non-consecutive days, across 3 reagent lots. This results in $7 \times 6 \times 3 \times 6 = 756$ individual test results reported (though the table summarizes 108 tests per panel member for overall agreement, implying 108 replicates per panel across sites/operators/days). Data provenance is likely laboratory-contrived samples (cultured organisms in negative pooled clinical vaginal swab matrix).
Multicenter Study with Untrained Operators:
- Sample Size: 102 samples initially selected; 1 was excluded, so 101 samples were included in the final analysis (30 CT positive, 20 NG positive, 30 TV positive, 33 negative based on comparator results, though the sum of these is 113, implying some overlap or specific positivity counts within the 101 total).
- Data Provenance: De-identified, frozen, self-collected vaginal swab specimens that are a subset of patient samples previously characterized in the clinical study for the Click Test. This indicates retrospective human clinical data from the U.S. (implied by FDA submission context, though not explicitly stated for this particular subset).
Single Center Study with Trained Operators:
- Sample Size: 359 specimens initially; 1 excluded due to insufficient volume, 7 excluded due to retest issues. Final analysis included 351 specimens.
- Data Provenance: De-identified, frozen, archived self-collected vaginal swab specimens in Visby Medical Collection Media. These included specimens from the original clinical study of the Click Test and from two other previous Visby Medical studies. This indicates retrospective human clinical data, likely from the U.S.
Contrived Specimens Spiked at Low Organism Concentrations:
- Sample Size: 80 contrived samples (20 CT positive, 20 NG positive, 20 TV positive, and 20 negative).
- Data Provenance: Laboratory-generated, spiked samples using individual clinical matrices.

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

The document mentions that for the Multicenter Study and Single Center Study:

The samples were "previously characterized in the clinical study for the Click Test" and "based on comparator results from the clinic study for Click Test."
"TV PIS (based on the original clinical study for Click Test) for all seven specimens were negative."

This strongly implies that the ground truth for these clinical test sets was established during the clinical studies for the predicate device (Click Test). The report for the current device (Visby Test) does not detail the specific number or qualifications of experts for establishing the ground truth for these retrospective samples, as that would have been documented in the original predicate device's submission. It refers to "comparator results," which typically means a highly sensitive and specific reference method (e.g., PCR with bidirectional sequencing, culture followed by definitive identification) performed and interpreted by qualified laboratory personnel, rather than a panel of clinical experts adjudicating cases for complex imaging or clinical diagnoses.

For the LoD and Contrived samples studies, the "ground truth" is known by design, as the samples are deliberately spiked with known concentrations of organisms.

4. Adjudication Method for the Test Set

The document does not describe a formal adjudication method (like 2+1 or 3+1) for establishing the ground truth in the context of clinical samples.

For the multicenter and single-center clinical studies, the reference standard (ground truth) was based on "comparator results" from the original clinical studies of the predicate device. This typically implies a highly accurate lab-based method.
For the reproducibility, LoD, and contrived sample studies, the ground truth was known by design (known presence/absence and concentration of spiked organisms).

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance

This device is an in vitro diagnostic (IVD) test that directly detects nucleic acids via PCR and provides a visually interpreted result. It is not an AI-based imaging analysis tool or a system that "assists human readers" in the way an MRMC study would typically evaluate for AI in radiology or pathology. The "operators" are interpreting the device's output (presence of a purple spot), not interpreting complex data that AI might enhance. Therefore, an MRMC comparative effectiveness study for human readers with and without AI assistance is not applicable and was not done.

The studies performed evaluate the performance of the device itself when operated by different user groups (trained vs. untrained) and compared to a predicate device.

6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done

The Visby Medical Sexual Health Test is a fully integrated, automated PCR diagnostic test that provides a visual result (purple spot). The results are then visually interpreted by an operator ("Operator visually interprets test results" - pg 6). While the internal PCR process is automated, the final "reading" is done by a human looking at the colorimetric output. Therefore, it's not a purely "algorithm-only" device without human intervention for result interpretation. However, the performance data presented (PPA/NPA) reflects the device's accuracy in producing the correct visual output, as subsequently interpreted by a human operator. The studies demonstrate the performance of the device system including human interpretation in different use environments.

7. The Type of Ground Truth Used

Clinical Comparison Studies (Multicenter and Single Center): The ground truth was established by "comparator results" from the original clinical studies of the predicate device (Visby Medical Sexual Health Click Test). This typically refers to a highly accurate laboratory-based reference method, such as a laboratory-developed test (LDT) using PCR with sequencing confirmation, or culture followed by definitive identification, considered the gold standard for detecting these pathogens.
LoD, Reproducibility, and Contrived Samples Studies: The ground truth was established by design, using cultured organisms spiked at known concentrations into negative clinical matrices.

8. The Sample Size for the Training Set

The document describes performance data for the Visby Medical Sexual Health Test, which is an "updated version of the Visby Medical Sexual Health Click test (Click Test, the predicate)." It explicitly states that "The Visby Test has no changes to the PCR primer and probe sequences, reagent formulations, detection method, or result interpretations."

Since this is an updated version of an existing device with no changes to the core diagnostic method (PCR primers, probes, detection), it's highly unlikely that a separate "training set" in the context of machine learning model development was used for this specific device. The document focuses on demonstrating equivalence to the predicate device. If the predicate device (Click Test) involved any form of algorithm development requiring a training set, that would have been part of its original 510(k) submission (K200748/CW200003). For the current submission, the studies are primarily verification and validation, showing that the new manufacturing process and simplified user interface do not negatively impact performance compared to the predicate.

Therefore, a sample size for a training set for the Visby Medical Sexual Health Test is not applicable / not provided in this document.

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

As mentioned in point 8, a "training set" for an algorithm is not described or applicable to the type of update this device represents. If the predicate device (Click Test) had a training set, the ground truth for that would have been established according to its original clearance. This document focuses on demonstrating equivalence of the updated physical device.

Summary

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March 7, 2023

Image /page/0/Picture/1 description: The image contains the logo of the U.S. Food and Drug Administration (FDA). On the left is the Department of Health & Human Services logo. To the right of that is the FDA logo, which is a blue square with the letters "FDA" in white. To the right of the FDA logo is the text "U.S. FOOD & DRUG ADMINISTRATION" in blue.

Visby Medical Beth Lingenfelter Vice President Regulatory and Clinical Affairs 3010 N 1st Street San Jose, California 95134

Re: K220407

Trade/Device Name: Visby Medical Sexual Health Test Regulation Number: 21 CFR 866.3393 Regulation Name: Device To Detect Nucleic Acids From Non-Viral Microorganism(S) Causing Sexually Transmitted Infections And Associated Resistance Marker(S) Regulatory Class: Class II Product Code: QEP, MKZ, LSL, OUY Dated: February 10, 2022 Received: February 14, 2022

Dear Beth Lingenfelter:

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. Although this letter refers to your product as a device, please be aware that some cleared products may instead be combination products. The 510(k) Premarket Notification Database located at https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm identifies combination product submissions. 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

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requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part 801 and Part 809); medical device reporting of medical device-related adverse events) (21 CFR 803) for devices or postmarketing safety reporting (21 CFR 4, Subpart B) for combination products (see https://www.fda.gov/combination-products/guidance-regulatory-information/postmarketing-safety-reportingcombination-products); good manufacturing practice requirements as set forth in the quality systems (OS) regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR 4, Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.

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 https://www.fda.gov/medical-device-safety/medical-device-reportingmdr-how-report-medical-device-problems.

For comprehensive regulatory information about mediation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/medicaldevices/device-advice-comprehensive-regulatory-assistance) and CDRH Learn (https://www.fda.gov/training-and-continuing-education/cdrh-learn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See the DICE website (https://www.fda.gov/medical-device-advice-comprehensive-regulatoryassistance/contact-us-division-industry-and-consumer-education-dice) for more information or contact DICE by email (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).

Sincerely,

Himani Bisht -S

Himani Bisht, Ph.D. Assistant Director Viral Respiratory and HPV Branch Division of Microbiology Devices OHT7: Office of In Vitro Diagnostics Office of Product Evaluation and Quality Center for Devices and Radiological Health

Enclosure

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Indications for Use

510(k) Number (if known) K220407

Device Name Visby Medical Sexual Health Test

Indications for Use (Describe)

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

A. Submitter

Name:	Visby Medical, Inc.
Address:	3010 N. First Street
	San Jose, CA 95134
Phone:	1-833-468-4729
Contact:	Beth Lingenfelter
Date Prepared:	January 20, 2023
Device
Name of Device:	Visby Medical Sexual Health Test
Common Name:	Same
Classification Name:	Device to Detect Nucleic Acids from Non-Viral
	Microorganism(s) Causing Sexually Transmitted Infections
	and Associated Resistance Marker(s)
Regulatory Classification:	Class II
Regulation:	21 CFR 866.3393
Primary Product Code:	QEP
Additional Product Codes:	MKZ, LSI, and QUY

C. Predicate Device

Visby Medical Sexual Health Click Test (K200748/CW200003)

D. Device Description

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control. The sample enters a lysis module, where the DNA of the sample and the internal process control are extracted using a combination of chemical lysis and high temperature. The extracted DNA enters a mixing chamber where it rehydrates lyophilized PCR reagents, followed by thermocycling to amplify target DNA. If present, the amplified pathogen target (CT, NG, and/or TV) and internal process control hybridize to specific probes located on a flow channel. Detection of the target-specific PCR product is accomplished via an enzyme-linked colorimetric assay using streptavidin bound horseradish peroxidase (HRP) and a colorimetric substrate that forms a purple precipitate. Test results can be expected in approximately 30 minutes: a green check mark will appear, and a purple color will appear in the "Results Valid" spot, indicating a valid test. A purple spot adjacent to "Chlamydia," "Gonorrhea," and/or "Trichomoniasis" signifies the presence of amplified CT, NG, and/or TV DNA in the sample.

E. Intended Use

The Visby Medical Sexual Health Test is a single-use (disposable), fully integrated, automated Polymerase Chain Reaction (PCR) in vitro diagnostic test intended for use in point-of-care or clinical laboratory settings for the rapid detection and differentiation of DNA from Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis in self-collected female vaginal swab specimens using Visby Medical Sexual Health Vaginal Specimen Collection Kit in a health care setting. The test results are to aid in the diagnosis of symptomatic or asymptomatic infections with Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis.

F. Substantial Equivalence

The Visby Test is an updated version of the Visby Medical Sexual Health Click test (Click Test, the predicate). The Visby Test has no changes to the PCR primer and probe sequences, reagent formulations, detection method, or result interpretations.

Both devices have a similar design and are composed of the same materials. The Visby Test was developed to further simplify the user interface and to enable the automated manufacture process of the device,

The following table compares the Visby Test to the Click Test and outlines the similarities between the two tests.

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Characteristics	PredicateClick Test	Subject DeviceVisby Test
Principle ofOperation	An automated multiplex polymerasechain reaction with colorimetricdetection.	Same
Analyte	DNA	Same
OrganismsDetected	Chlamydia trachomatis (CT)Neisseria gonorrhoeae (NG)Trichomonas vaginalis (TV)	Same
PatientPopulation	Asymptomatic and symptomatic femalepatients	Same
Intended Use	The Visby Medical Sexual HealthClick Test is a single-use (disposable),fully integrated, automated PolymeraseChain Reaction (PCR) in vitrodiagnostic test intended for use in point-of-care or clinical laboratory settings forthe rapid detection and differentiation ofDNA from Chlamydia trachomatis,Neisseria gonorrhoeae, andTrichomonas vaginalis in self-collectedfemale vaginal swab specimenscollected using Visby Medical SexualHealth Vaginal Specimen Collection Kitin a health care setting. The test resultsare to aid in the diagnosis ofsymptomatic or asymptomatic infectionswith Chlamydia trachomatis, Neisseriagonorrhoeae, and Trichomonasvaginalis.	Same, only change is to the name of thedevice.The Visby Medical Sexual Health Testis a single-use (disposable), fullyintegrated, automated Polymerase ChainReaction (PCR) in vitro diagnostic testintended for use in point-of-care or clinicallaboratory settings for the rapid detectionand differentiation of DNA fromChlamydia trachomatis, Neisseriagonorrhoeae, and Trichomonas vaginalisin self-collected female vaginal swabspecimens collected using Visby MedicalSexual Health Vaginal SpecimenCollection Kit in a health care setting. Thetest results are to aid in the diagnosis ofsymptomatic or asymptomatic infectionswith Chlamydia trachomatis, Neisseriagonorrhoeae, and Trichomonas vaginalis.
Specimen Type	Patient-collected vaginal swab in VisbyCollection Media	Same
CLIA ComplexityLevel	CLIA waived	Same
Quality Control	Internal electronic and process controlsExternal Controls (by Zeptometrix)	Same
Characteristics	PredicateClick Test	Subject DeviceVisby Test
Reagents	Target specific primersTarget specific capture probesLyophilized PCR reagentEnzyme linked colorimetric reagents ofvisualization of target amplicon	Same
	Resultsinterpretation	Operator visually interprets test results	Same
	Time to result	Approximately 30 minutes	Same

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G. Summary of Performance Data

Comparison of Limit of Detection between the Visby Test and Click Test

This study provides objective evidence that the LoD for the Visby Test is comparable to that of the Click Test. Negative pooled clinical vaginal sample in Visby Collection Media was spiked at the LoD that was established with the Click Test and tested with 20 Visby devices and 20 Click devices. If at least 19/20 devices returned a positive test result, the organism was diluted 3-fold and the testing was repeated until the detection rate was <19/20 for both the Click and Visby test. The LoD values were determined to be equivalent if the lowest concentrations of organism with at least 19/20 detection rate from the two devices were within 3-fold of each other. The results in Table 1 confirm that the LoD between the Click Test and Visby Test are comparable.

Organism	LoD Multiple	TargetConcentration	Hit Rate (Positive Valid Devices /Total Valid Devices Tested)
			Click Test	Visby Test
CT SerovarH (VR-879)	1x	16.00 EB/mL	20/20	20/20
	1/3x	5.33 EB/mL	13/20	18/20
CT SerovarD (VR-885)	1x	5.90 EB/mL	20/20	20/20
	1/3x	1.97 EB/mL	11/20	19/20
	1/9x	0.66 EB/mL	7/20	10/20
NG	1x	6.20 cfu/mL	19/20	20/20
	1/3x	2.06 cfu/mL	10/20	19/20

Table 1. LoD comparison between Visby Test and the Click Test

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(ATCC49226)	1/9x	0.68 cfu/mL	5/20	9/20
NG(ATCC19424)	3x	17.1 cfu/mL	20/20	20/20
	1x	5.7 cfu/mL	17/20	20/20
	1/3x	1.9 cfu/mL	17/20	19/20
	1/9x	0.63 cfu/mL	8/20	9/20
TV(ATCC30001)	1x	1.20 troph/ mL	19/20	20/20
	1/3x	0.40 troph/mL	20/20	19/20
	1/9x	0.13 troph/mL	16/20	16/20
TV(ATCC30238)	1x	0.24 troph/mL	20/20	20/20
	1/3x	0.08 troph/mL	17/20	17/20

Reproducibility

The reproducibility study of the Visby Test was conducted at three (3) CLIA waived study sites. The operators performing the testing were non-laboratorians representing healthcare professionals that may be encountered at such sites. The study evaluated seven (7) panel members that were prepared using cultured organisms in negative pooled clinical vaginal swab matrix (previously determined to be negative for CT, NG, TV). The study was performed with negative (unspiked), low positive (1X LoD), and moderate positive (3-5X LoD) samples.

A total of six (6) study operators (2 operators at each site) tested the panel three (3) times each testing day, over six (6) non-consecutive days. Three reagent lots were used in the study. A summary of the results (count correct / total count) and % agreement with expected results for each panel member by site and overall is presented in Table 2.

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	Site 1	Site 2	Site 3	Overall Agreement
Panel Member	% Agreement(count)	% Agreement(count)	% Agreement(count)	% Agreement(count)	95% CI
CT Moderate Positive(64.0 EB/mL)	100.0%(36/36)	100.0%(36/36)	100.0%(36/36)	100.0%(108/108)	96.6%-100.0%
CT Low Positive(16.0 EB/mL)	97.2%(35/36)	100.0%(36/36) a	100.0%(36/36)	99.1%(107/108)	94.9%-99.8%
NG Moderate Positive(24.8 cfu/mL)	100.0%(36/36)	100.0%(36/36)	97.2%(35/36)	99.1%(107/108)	94.9%-99.8%
NG Low Positive(6.2 cfu/mL)	100.0%(36/36)	100.0%(36/36)	100.0%(36/36)	100.0%(108/108)	96.6%-100.0%
TV ModeratePositive(4.8 troph/mL)	100.0%(36/36)	100.0%(36/36)	100.0%(36/36)	100.0%(108/108)	96.6%-100.0%
TV Low Positive(1.2 troph/mL)	97.2%(35/36)	97.2%(35/36) b	94.4%(34/36)	96.3%(104/108)	90.9%-98.6%
Negative	97.2%(35/36) c	100.0%(36/36)	97.2%(35/36) c	98.1%(106/108)	93.5%-99.5%

Table 2. Summary of Reproducibility Study Results for the Visby Test

a One CT Low Positive sample was unexpectedly positive for TV

b One TV Low Positive sample was unexpected positive for CT

C One Neqative sample was unexpectedly positive for TV

Clinical Comparison Study

Three studies were conducted to evaluate the equivalence of performance between the Visby Test and the Click Test.

Multicenter study with Untrained Operators

This study was conducted in CLIA Waived (CW) testing environments at three study sites using de-identified, frozen, self-collected vaginal swab specimens that are a subset of patient samples previously characterized in the clinical study for the Click Test.

A total of 30 CT positive (based on comparator results from the clinic study for Click Test, and this is the same for other analytes and negative sample), 20 NG positive, 30 TV positive and 33 negative vaginal swab specimens were selected for the study. Six (6) untrained study operators (two operators at each site) conducted the Visby testing.

The frozen samples were de-identified, randomized, and blinded so that the study staff and test operators did not know the expected results. Operators thawed the samples and tested them on-site using the Visby Test by following the instructions in the Quick Reference Guide (QRG). The results of the Visby Test were compared to the recorded result of the Click Test. Of the 102 samples included in the study, two samples had an initial invalid test result (2.41%, 95% Cl: 0.66%-8.37%). One sample was excluded from the data analysis because it was invalid upon retesting. There were no additional

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exclusions. Table 3 summarizes the concordance between the Click test results and the Visby test results.

Target	N	TP	FP	TN	PPA (95% CI)	NPA (95% CI)
CT	101	30	0	71	100.0%(88.6%-100.0%)	100%(94.9%-100.0%)
NG	101	20	0	81	100.0%(83.9%-100.0%)	100.0%(95.5%-100.0%)
TV	101	30	3	68	100.0%(88.6%-100.0%)	95.8%(88.3%-98.6%)

Table 3. Clinical Performance of the Visby Test compared to the Click test performed by untrained operators

PPA=Positive Percent agreement: NPA=Negative Percent Agreement

TP=true positive; FP=false positive; TN=true negative; FN=false negative.

Single Center Study with Trained Operators

A second clinical method comparison study was conducted at one site by trained operators using de-identified, frozen, archived self-collected vaginal swab specimens in Visby Medical Collection Media. The specimens tested in this study include all specimens with sufficient volume from the original clinical study of the Click Test as well as archived and banked frozen self-collected samples from two other previous Visby Medical studies. Testing was conducted by seven trained operators over seven days under variable lighting conditions throughout the day. The specimens were randomized and blinded so that the test operators did not know the expected results.

A total of 359 specimens were tested in this study. Operators thawed the samples and tested them with both the Visby Test and the Click Test if sufficient sample volume was present. Specimens without sufficient volume to run on both devices were tested only on the Visby Test, and the original Click Test results were used for the comparison.

Of the 359 specimens included in the study, one specimen did not have sufficient volume to run on any test and thus was excluded from the study. Of the remaining 358 specimens tested on the Visby Test, 11 (3.1%) had an initial invalid test result. As a final result, seven specimens were excluded from performance calculation due to insufficient sample volume for retest or failure to obtain a valid retest result. Therefore, a total of 351 specimens were included in the performance table.

Table 4 summarizes the concordance of the results between the Click Test and the Visby Test.

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Visby Test vs. Click Test
Target	N	TP	FP	TN	FN	PPA	NPA
CT	351	116	3	232	0	100.0% (95% CI:96.8% - 100.0%)	98.7% (95% CI:96.3% - 99.6%)
NG	351	34	0	317	0	100.0% (95% CI:89.9% - 100.0%)	100.0% (95% CI:98.8% - 100.0%)
TV	351	100	4	240	7a	93.5% (95% CI:87.1% - 96.8%)	98.4% (95% CI:95.9% - 99.4%)

Table 4. Performance of Visby Test Compared to Click Test - Clinical Specimens

a. TV PIS (based on the original clinical study for Click Test) for all seven specimens were negative.

Contrived specimens spiked at low organism concentrations

To further evaluate the performance of the Visby Test with samples containing low levels of the target organisms, samples were spiked at 1.5x LoD, 2x LoD and 3x LoD levels for each target in individual clinical matrices. Twenty (20) CT positive, 20 NG positive, 20 TV positive and 20 negative samples were tested on both the Visby Test and Click Test by four trained operators at a single site. Testing was performed over two days under various lighting conditions in a randomized and blinded fashion. All 80 contrived samples yielded valid results and are included in the final data analysis.

Table 5 summarizes the concordance of the results between the Visby Test and the Click Test when testing contrived samples.

Organism	Concentration	Correct Results / Total Tested
		Click Test	Visby Test
CT	1.5x LoD	6/6	5/6
CT	2x LoD	10/10	9/10
CT	3x LoD	4/4	4/4
NG	1.5x LoD	5/6	5/6
NG	2x LoD	9/10	10/10
NG	3x LoD	4/4	4/4
TV	1.5x LoD	6/6	6/6
TV	2x LoD	10/10	10/10
TV	3x LoD	4/4	4/4
Negative	N/A	20/20	19/20*
* One device was unexpectedly positive for TV

Table 5. Performance of Visby Test Compared to Click Test - Contrived Samples

One device was unexpectedly positive for TV

Regulation Number and Section

§ 866.3393 Device to detect nucleic acids from non-viral microorganism(s) causing sexually transmitted infections and associated resistance marker(s).

(a)
Identification. A device to detect nucleic acids from non-viral microorganism(s) causing sexually transmitted infections and associated resistance marker(s) is an in vitro diagnostic device intended for the detection and identification of nucleic acids from non-viral microorganism(s) and their associated resistance markers in clinical specimens collected from patients suspected of sexually transmitted infections. The device is intended to aid in the diagnosis of non-viral sexually transmitted infections in conjunction with other clinical and laboratory data. These devices do not provide confirmation of antibiotic susceptibility since mechanisms of resistance may exist that are not detected by the device.(b)
Classification. Class II (special controls). The special controls for this device are:(1) The intended use for the labeling required under § 809.10 of this chapter must include a detailed description of targets the device detects, the results provided to the user, the clinical indications appropriate for test use, and the specific population(s) for which the device is intended.
(2) Any sample collection device used must be FDA-cleared, -approved, or -classified as 510(k) exempt (standalone or as part of a test system) for the collection of specimen types claimed by this device; alternatively, the sample collection device must be cleared in a premarket submission as a part of this device.
(3) The labeling required under § 809.10(b) of this chapter must include:
(i) A detailed device description, including reagents, instruments, ancillary materials, all control elements, and a detailed explanation of the methodology, including all pre-analytical methods for processing of specimens;
(ii) Detailed discussion of the performance characteristics of the device for all claimed specimen types based on analytical studies, including Limit of Detection, inclusivity, cross-reactivity, interfering substances, competitive inhibition, carryover/cross contamination, specimen stability, within lab precision, and reproducibility, as appropriate;
(iii) Detailed descriptions of the test procedure, the interpretation of test results for clinical specimens, and acceptance criteria for any quality control testing;
(iv) Limiting statements indicating that:
(A) A negative test result does not preclude the possibility of infection;
(B) The test results should be interpreted in conjunction with other clinical and laboratory data available to the clinician;
(C) Reliable results are dependent on adequate specimen collection, transport, storage, and processing. Failure to observe proper procedures in any one of these steps can lead to incorrect results; and
(D) If appropriate (
e.g., recommended by the Centers for Disease Control and Prevention, by current well-accepted clinical guidelines, or by published peer reviewed research), that the clinical performance is inferior in a specific clinical subpopulation or for a specific claimed specimen type; and(v) If the device is intended to detect antimicrobial resistance markers, limiting statements, as appropriate, indicating that:
(A) Negative results for claimed resistance markers do not indicate susceptibility of detected microorganisms, as resistance markers not measured by the assay or other potential mechanisms of antibiotic resistance may be present;
(B) Detection of resistance markers cannot be definitively linked to specific microorganisms and the source of a detected resistance marker may be an organism not detected by the assay, including colonizing flora;
(C) Detection of antibiotic resistance markers may not correlate with phenotypic gene expression; and
(D) Therapeutic failure or success cannot be determined based on the assay results, since nucleic acid may persist following appropriate antimicrobial therapy.
(4) Design verification and validation must include:
(i) Detailed device description documentation, including methodology from obtaining sample to result, design of primer/probe sequences, rationale for target sequence selection, and computational path from collected raw data to reported result (
e.g., how collected raw signals are converted into a reported result).(ii) Detailed documentation of analytical studies, including, Limit of Detection, inclusivity, cross-reactivity, microbial interference, interfering substances, competitive inhibition, carryover/cross contamination, specimen stability, within lab precision, and reproducibility, as appropriate.
(iii) Detailed documentation and performance results from a clinical study that includes prospective (sequential) samples for each claimed specimen type and, when determined to be appropriate by FDA, additional characterized clinical samples. The study must be performed on a study population consistent with the intended use population and compare the device performance to results obtained from FDA accepted comparator methods. Documentation from the clinical studies must include the clinical study protocol (including a predefined statistical analysis plan) study report, testing results, and results of all statistical analyses.
(iv) A detailed description of the impact of any software, including software applications and hardware-based devices that incorporate software, on the device's functions.