(89 days)
The LIAISON® Treponema Assay and the LIAISON® Treponema Serum Controls uses chemiluminescence immunoassay (CLIA) technology for the qualitative detection of total antibodies of any class (IqG/IgM) directed against Treponema pallidum in human serum. The presence of antibodies to Treponema pallidum specific antigen, in conjunction with nontreponemal laboratory tests and clinical findings, may aid in the diagnosis of syphilis infection. The LIAISON® Treponema Assay is not intended for use in the screening of blood or plasma donors.
The method for determination of specific total antibodies to Treponema pallidum is a one-step chemiluminescence immunoassay (CLIA). All assay steps and incubations are performed by the LIAISON® Analyzer, with the exception of initial magnetic particle resuspension. Recombinant antigens specific for Treponema pallidum are used for coating the magnetic particles (solid phase) and are used in the tracer when linked to an isoluminol derivative (isoluminol-antigen conjugate). During the incubation step antibodies present in the calibrators, samples or controls bind to the solid phase. The conjugate reacts with the antibodies already bound to the solid phase. After the incubation, the unbound material is removed with a wash cycle. Subsequently, the starter reagents are added and a flash Chemiluminescence reaction is induced. The light signal and hence the amount of isoluminol-antigen conjugate is measured by a photomultiplier as relative light units (RLU) and is indicative of total antibodies to Treponema pallidum present in calibrators, controls or samples.
Here's a breakdown of the acceptance criteria and study information for the DiaSorin LIAISON® Treponema Assay, based on the provided text:
Acceptance Criteria and Device Performance
The acceptance criteria are implied by the "Percent Agreement" values achieved by the device in comparison to a predicate device (Trinity CAPTIA™ Syphilis (T.pallidum) G) and adjudicated results. While explicit pre-defined thresholds for "acceptance" are not stated, the high agreement percentages are presented as evidence that the device meets its intended use.
| Acceptance Criteria Category (Implied by Study) | Acceptance Criteria (Implied) | Reported Device Performance (LIAISON® Treponema Assay) |
|---|---|---|
| Study 1: Clinical Laboratory Screen Test | ||
| Medically Diagnosed Syphilis Infection | High Positive Agreement | 97.7% (95% CI = 94.9 – 99.2%) after resolution |
| High Negative Agreement | N/A (Focus on Positive) | |
| High Overall Agreement | 97.7% (95% CI = 94.9 – 99.2%) after resolution | |
| Samples sent for Syphilis testing | High Positive Agreement | N/A (Focus on Overall) |
| High Negative Agreement | N/A (Focus on Overall) | |
| High Overall Agreement | 98.7% (95% CI = 97.8 - 99.3%) after resolution | |
| HIV Positive Samples | High Positive Agreement | N/A (Focus on Overall) |
| High Negative Agreement | N/A (Focus on Overall) | |
| High Overall Agreement | 94.5% (95% CI = 90.4 – 97.2%) after resolution | |
| Pregnancy Samples | High Positive Agreement | 100% (95% CI = 98.2 – 100%) after resolution |
| High Negative Agreement | 100% (95% CI = 98.2 – 100%) after resolution | |
| High Overall Agreement | 100% (95% CI = 98.2 – 100%) after resolution | |
| Apparently Healthy Adults | High Positive Agreement | N/A (Focus on Overall) |
| High Negative Agreement | N/A (Focus on Overall) | |
| High Overall Agreement | 98.3% (95% CI = 97.3 - 99.0%) after resolution | |
| Study 2: Diagnostic Confirmatory Test | ||
| RPR/VDRL Positive Samples | High Positive Agreement | 100% (95% CI = 98.2 - 100%) after resolution |
| High Negative Agreement | N/A (Focus on Positive) | |
| High Overall Agreement | 100% (95% CI = 98.2 - 100%) after resolution |
Study Details
-
Sample Sizes Used for the Test Set and Data Provenance:
- Study 1 (Clinical Laboratory Screen Test):
- Medically Diagnosed Syphilis Infection: n=178 (51 from US, 127 from Europe). Retrospective.
- Laboratory samples sent for Syphilis testing: n=999. Prospective.
- HIV Positive Samples: n=200. Prospective.
- Pregnancy Samples: n=200. Prospective.
- Apparently Healthy Adults: n=992. Prospective.
- Study 2 (Diagnostic Confirmatory Test):
- RPR/VDRL Positive Samples: n=204. Retrospective.
Overall, data provenance includes both retrospective and prospective samples from the US and Europe.
- Study 1 (Clinical Laboratory Screen Test):
-
Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of those Experts:
The document does not explicitly state the number or qualifications of experts establishing the initial ground truth for the test set. However, it mentions "Medically Diagnosed Syphilis infection" samples, implying clinical diagnosis by medical professionals. The comparator device (Trinity CAPTIA™ Syphilis (T.pallidum) G) was used as the primary comparative method. -
Adjudication Method for the Test Set:
Discordant samples between the LIAISON® Treponema Assay and the comparator Trinity CAPTIA™ kit were further tested. The adjudication method involved:- Repeating equivocal results in duplicate on both the Trinity CAPTIA™ kit and the LIAISON® Treponema assay.
- Repeating all positive samples on the Trinity CAPTIA™ kit in duplicate.
- Testing discordant samples with a non-treponemal test (RPR) and another treponemal kit (TP-PA) capable of detecting total antibodies.
- The resolution of discordants was carried out following the Algorithm suggested by Victoria Pope Ph.D.
This implies a type of reflex testing and expert-informed consensus/algorithm-based resolution using multiple established methods (RPR, TP-PA) to determine the final ground truth for discordant samples.
-
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:
No, a Multi-Reader Multi-Case (MRMC) comparative effectiveness study was not done. This study is for an immunoassay device and does not involve human readers interpreting images or data to be assisted by AI. The comparison is between two automated laboratory tests. -
If a Standalone (i.e. algorithm only without human-in-the-loop performance) was Done:
Yes, this was a standalone performance study. The LIAISON® Treponema Assay itself is an automated chemiluminescence immunoassay (CLIA) device. The performance data presented are for the device's output (qualitative detection of antibodies) compared to another lab test, without human interpretation as part of the primary outcome measure. -
The Type of Ground Truth Used (expert consensus, pathology, outcomes data, etc):
For the initial unadjudicated results, the ground truth was largely based on the results of the predicate device (Trinity CAPTIA™ Syphilis (T.pallidum) G), along with clinical diagnosis for "Medically Diagnosed Syphilis Infection" samples. For discordant samples, the ground truth was established through a combination of confirmatory laboratory tests (RPR, TP-PA) and an established clinical algorithm (Victoria Pope Ph.D.'s algorithm). This suggests a form of expert-informed consensus based on a diagnostic algorithm and multiple laboratory tests. -
The Sample Size for the Training Set:
The document does not mention a separate "training set" for the DiaSorin LIAISON® Treponema Assay. Immunoassays typically do not have a training set in the same way machine learning algorithms do. The "development" of the assay would involve internal optimization using various known samples, but these are not explicitly detailed as a distinct "training set" in the context of this regulatory submission which focuses on the clinical validation/test set. -
How the Ground Truth for the Training Set was Established:
As no explicit training set is detailed, information on how its ground truth was established is not provided.
{0}------------------------------------------------
K061247
JUL 3 1 2006
510(k) SUMMARY
SUBMITTED BY:
Carol A. DePouw Regulatory Affairs Specialist DiaSorin Inc. 1951 Northwestern Avenue P.O. Box 285 Stillwater, MN 55082-0285 Phone (651) 351-5850 Fax (651) 351-5669 Email: carol.depouw@diasorin.com
NAME OF DEVICE:
| Trade Name: | DiaSorin LIAISON® Treponema Assay |
|---|---|
| Common Names/Descriptions: | Immunoassay for the detection of antibodies toTreponema pallidum to aid in the diagnosis ofSyphilis in human serum |
| Classification Names: | Treponema pallidum treponemal test reagents |
| Product Code: | LIP |
| Trinity CAPTIA™ Syphilis (T. Pallidum) G(K014233) |
DEVICE DESCRIPTION:
PRE
INTENDED USE: The LIAISON® Treponema assay uses chemiluminescence immunoassay (CLIA) technology for the qualitative detection of total antibodies of any class (IqG/IqM) directed against Treponema pallidum in human serum.
The presence of antibodies to Treponema pallidum specific antigen, in conjunction with non treponemal laboratory tests and clinical findings, may aid in the diagnosis of syphilis infection.
The LIAISON® Treponema Assay is not intended for use in screening blood or plasma donors.
KIT DESCRIPTION: The method for determination of specific total antibodies to Treponema pallidum is a one-step chemiluminescence immunoassay (CLIA).
All assay steps and incubations are performed by the LIAISON® Analyzer, with the exception of initial magnetic particle resuspension.
Recombinant antigens specific for Treponema pallidum are used for coating the magnetic particles (solid phase) and are used in the tracer when linked to an isoluminol derivative (isoluminol-antigen conjugate). During the incubation step antibodies present in the calibrators, samples or controls bind to the solid phase. The conjugate reacts
{1}------------------------------------------------
with the antibodies already bound to the solid phase. After the incubation, the unbound material is removed with a wash cycle.
Subsequently, the starter reagents are added and a flash Chemiluminescence reaction is induced. The light signal and hence the amount of isoluminol-antigen conjugate is measured by a photomultiplier as relative light units (RLU) and is indicative of total antibodies to Treponema pallidum present in calibrators, controls or samples,
PERFORMANCE DATA:
Performance testing of the LIAISON® Treponema Assay for comparative clinical trials consisted of running selected samples for two (2) studies to support the intended use.
Study 1: Clinical Laboratory Screen Test (Treponemal Test followed by a Non-Treponemal test). This study consisted of samples from:
Medically Diagnosed Syphilis infection (Retrospective samples n=51 patients from the US and n =127 patients from Europe) Total n = 178.
Laboratory samples sent for Syphilis HIV Positive Samples (Prospective n=999) Pregnancy Samples (Prospective n=200)
Apparently Healthy Adults (Prospective n = 992)
Study 2: Diagnostic Confirmatory test (Traditional testing algorithm a non-treponemal test followed by a Treponemal test.) This study consists of: RPR/VDRL positive samples (Retrospective n=204).
COMPARATIVE CLINICAL TRIALS: The clinical trials were conducted at two external US laboratories and at DiaSorin,Inc. Testing was performed on prospective and retrospective samples as described in the two clinical studies above. The samples were tested by LIAISON® Treponema Assay and the comparator assay Trinity CAPTIA™ Syphilis (T.pallidum) G at the trial sites per the manufacturer's instructions for use. Discordant samples were further tested by RPR and TP-PA per the recommendations for non-treponemal testing and use of another treponemal method when following the algorithm to Screen for Syphilis: (Treponema Test as Screen) from (Use of Treponemal Tests to Screen for Syphilis, by Victoria Pope, PhD, Infect. Med 21 (8):399-404, 2004 Cliggottt Publishing Division of CMP Healthcare Media).
Image /page/1/Figure/11 description: This image is a flowchart that describes the process for testing for syphilis. The flowchart starts with an EIA test, and then branches out depending on the results. The flowchart includes tests such as the RPR test, TP-PA test, and FTA-ABS test. The flowchart also includes possible outcomes such as "Not syphilis", "Syphilis", and "Late latent or treated?"
{2}------------------------------------------------
Study 1: Clinical Laboratory Screen Test
Medically Diagnosed Syphilis Infection – One Hundred Seventy-eight samples with different stages of syphilis. Fifty one of the samples were from the US and 127 were from Europe.
| Percent Agreement | 95% Exact Confidence Interval | |
|---|---|---|
| Positive | 98.8%(165/167) | 96.3 - 99.8% |
| Negative | 16.7%(1/6) | 8.5-58.1% |
| Overall | 93.3%(166/178) | 89.3 - 96.1% |
Samples sent to Laboratory for Syphilis testing – Nine Hundred Ninety-nine samples.
| PercentAgreement | 95% Exact Confidence Interval | |
|---|---|---|
| Positive | 55% (22/40) | 38.6 - 70.7% |
| Negative | 98.9% (909/919) | 98.0 - 99.5% |
| Overall | 93.2% (931/999) | 91.4 - 94.7% |
HIV positive samples – Two Hundred samples.
| PercentAgreement | 95% Exact Confidence Interval | |
|---|---|---|
| Positive | 75.8% (61/91) | 65.8 – 83.5% |
| Negative | 96.2% (100/104) | 90.4 - 98.9% |
| Overall | 84.5% (169/200) | 78.7 - 89.2% |
Pregnancy Samples - Two Hundred samples from pregnant women.
| Percent | |||
|---|---|---|---|
| Agreement | 95% Exact Confidence Interval | ||
| Positive | 100% | (4/4) | 38.9 - 100% |
| Negative | 100% | (192/192) | 98.1 - 100% |
| Overall | 98.0% | (200/200) | 95.0 - 99.5% |
Apparently Healthy Adults – Nine Hundred Ninety-two samples
| PercentAgreement | 95% Exact Confidence Interval | |
|---|---|---|
| Positive | 62.7% (54/86) | 51.7 – 73.0% |
| Negative | 99.3% (881/887) | 98.5 – 99.8% |
| Overall | 94.2% (935/992) | 92.6 – 95.6% |
{3}------------------------------------------------
Study 2: Diagnostic Confirmatory Test
| Percent Agreement | 95% Exact Confidence Interval | |
|---|---|---|
| Positive | 99.5% (200/201) | 98.2 - 100% |
| Negative | 100.0% (2/2) | 15.8 - 100% |
| Overall | 99.0% (202/204) | 97.3 - 100% |
RPR/VDRL Positive samples – Two Hundred four samples.
Conclusion:
Study 1:
The LIAISON® Treponema Assay demonstrated overall agreement with the comparator kit following the Algorithm to Screen for Syphilis: Treponema test as Screen: Medically Diagnosed Syphilis Samples, 93.3% (95% Cl = 89.3 - 96.1%) Samples sent to the Laboratory for Syphilis testing, 93.2% (95% Cl = 91.4 - 94.7%) HIV positive samples, 84.5% (95% Cl = 78.7 – 89.2%) Pregnancy samples, 98.0% (95% CI = 95.0 - 99.5%) Apparently Healthy Adults, 94.2% (95% CI = 92.6 - 95.6%)
The results demonstrate that the LIAISON® Treponema Assay can be used with the LIAISON® Analyzer for the qualitative detection of total antibodies in human serum when used as a clinical diagnostic screening test (not intended for use with blood donors or for screening the general population).
Study 2:
The LIAISON® Treponema Assay demonstrated overall agreement with the comparator kit for RPR/VDRL positive samples of 99.0% (95% Cl = 97.3 - 100%) when following the Traditional Algorithm: A non-treponemal test followed by a treponemal test.
The results demonstrate that the LIAISON® Treponema Assay can be used with the LIAISON® Analyzer for the qualitative detection of total antibodies in human serum when used as a diagnostic confirmatory test (not intended for use with blood donors
Equivocal, repeat and resolution testing.
All equivocal results were repeated in duplicate on the Trinity CAPTIA™ Syphilis (T. Pallidum)-G kit and the LIAISON® Treponema assay per the respective package inserts. All samples that were positive on the Trinity CAPTIA ™ kit were also repeated in duplicate per the package insert. Samples that were discordant between the Trinity CAPTIA™ kit and the LIAISON® Treponema kit were tested further with a nontreponemal test (RPR) and with a treponemal kit capable of picking up total antibodies (TP-PA). The resolution of the discordants was carried out by following the Algorithm suggested by Victoria Pope Ph.D, as shown above, and the percent agreements for positive, negative and overall were recalculated.
{4}------------------------------------------------
Study 1 - Resolved: Medically Diagnosed Syphilis Samples, 97.7% (95% CI = 94.9 -- 99.2%) Samples sent to the Laboratory for Syphilis testing, 98.7% (95% Cl = 97.8 - 99.3%) HIV positive samples, 94.5% (95% Cl = 90.4 ~ 97.2%) Pregnancy samples, 100% (95% CI = 98.2 – 100%) Apparently Healthy Adults, 98.3% (95% CI = 97.3 - 99.0%)
Study 2 - Resolved:
RPR/VDRL positive samples, 100% (95% Cl = 98.2 - 100%)
{5}------------------------------------------------
REPRODUCIBILITY: Reproducibility studies were performed at 3 sites using a coded panel comprised of 9 "engineered" serum samples. The same coded panel samples were tested at all 3 sites. Samples were run in 4 replicates per run for 5 days. The results expressed for Index and RLU's are summarized in the tables below. Samples 1007 and 1008 were negative samples that read below the limit of the curve so Index values were nondetectable.
| sampleID | N | meanIndex | withinrun%CV | betweenrun%CV | total (bysite)%CV | betweensite%CV | overall%CVIndex | overallsdIndex |
|---|---|---|---|---|---|---|---|---|
| 1001 | 60 | 0.94 | 4.90 | 4.19 | 6.27 | 5.76 | 7.91 | 0.07 |
| 1002 | 60 | 1.07 | 2.86 | 3.99 | 4.82 | 4.54 | 6.07 | 0.06 |
| 1003 | 60 | 1.42 | 3.03 | 3.57 | 5.34 | 7.02 | 8.08 | 0.11 |
| 1004 | 60 | 0.95 | 3.86 | 3.60 | 4.97 | 6.76 | 7.43 | 0.07 |
| 1005 | 60 | 0.99 | 2.62 | 6.22 | 6.35 | 6.81 | 8.60 | 0.09 |
| 1006 | 58 | 1.26 | 1.89 | 3.93 | 4.19 | 6.70 | 6.93 | 0.09 |
| 1007 | 58 | ND | ND | ND | ND | ND | ND | ND |
| 1008 | 60 | ND | ND | ND | ND | ND | ND | ND |
| 1009 | 60 | 13.13 | 3.11 | 3.75 | 5.45 | 4.87 | 6.93 | 0.91 |
| NC | 60 | 0.25 | 7.02 | 12.16 | 13.57 | 17.76 | 20.06 | 0.05 |
| PC | 60 | 5.06 | 2.70 | 4.94 | 4.78 | 5.76 | 7.28 | 0.37 |
Reproducibility Index
Reproducibility RLU
| sampleID | N | meanRLU | withinrun%CV | betweenrun%CV | total (bysite)%CV | betweensite%CV | overall%CVRLU | overallsdRLU |
|---|---|---|---|---|---|---|---|---|
| 1001 | 60 | 7845 | 4.72 | 4.31 | 6.41 | 5.52 | 7.87 | 617 |
| 1002 | 60 | 8901 | 2.70 | 3.95 | 4.82 | 4.55 | 6.07 | 540 |
| 1003 | 60 | 11873 | 1.94 | 4.52 | 5.75 | 7.58 | 8.76 | 1040 |
| 1004 | 60 | 7934 | 3.65 | 4.27 | 5.32 | 6.72 | 6.98 | 605 |
| 1005 | 60 | 8320 | 2.49 | 7.08 | 7.08 | 6.60 | 9.34 | 777 |
| 1006 | 58 | 10550 | 1.97 | 5.02 | 5.21 | 7.51 | 8.23 | 868 |
| 1007 | 58 | 1051 | 7.78 | 5.91 | 9.40 | 13.65 | 14.87 | 157 |
| 1008 | 60 | 1047 | 11.17 | 8.95 | 20.02 | 4.32 | 23.66 | 248 |
| 1009 | 60 | 105839 | 2.98 | 4.77 | 5.57 | 8.81 | 9.24 | 9778 |
| NC | 60 | 2027 | 6.19 | 6.19 | 9.26 | 16.04 | 15.94 | 323 |
| PC | 60 | 40799 | 3.44 | 4.95 | 5.89 | 10.84 | 10.70 | 4365 |
Conclusion:
The material submitted in this premarket notification supports a substantial equivalence claim. The labelling is sufficient and satisfies the requirements of 21CFR 809 10
{6}------------------------------------------------
Image /page/6/Picture/1 description: The image shows the logo for the U.S. Department of Health and Human Services. The logo consists of a stylized eagle with three lines representing its body and wings. The eagle is facing right. The logo is surrounded by a circular border with the words "U.S. Department of Health and Human Services" written around it.
Public Health Service
Food and Drug Administration 2098 Gaither Road Rockville MD 20850
Ms. Carol A. DePouw Regulatory Affairs Specialist DiaSorin, Inc. 1951 Northwestern Avenue P.O. Box 285 Stillwater, MN 55082-0285
JUL 3 1 2006
Re: K061247
Trade/Device Name: DiaSorin LIAISON® Treponema Assay Regulation Number: 21 CFR § 866.3830 Regulation Name: Enzyme-linked immunoabsorption assay, Treponema pallidum Regulatory Class: II Product Code: LIP Dated: July 21, 2006 Received: July 24, 2006
Dear Ms. DePouw:
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 iddictions 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 in microa in the devices that have been reclassified in accordance with the provisions of the Federal Food, Drig 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, isting of devices, good manufacturing practice, labeling, and prohibitions against misburanting 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 D2-: ' in a
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 medion wour not not incant 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 CFR Part 807); labeling (21 CFR Parts 801 and 809); 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(() rems rket notification. The FDA finding of substantial equivalence of your device to a logal y marketed predicate device results in a classification for your device and thus, permits your device to proceed to the market.
{7}------------------------------------------------
This letter will allow you to begin marketing your device as described in your Section 510(k) This setter will and w your to ough finding of substantial equivalence of your device to a legally premained newice 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, r you don't on the promotion and advertising of your device, please contact the Office of In of quostions on and proce Evaluation and Safety at (240)276-0450. Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21CFR Part 807.97). regulation entition on your responsibilities under the Act may be obtained from the Other general mionnation turers, 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,
Sally, attorn
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
{8}------------------------------------------------
4.0 INDICATIONS FOR USE
510(k) Number (if known): K061247
Device Name: LIAISON® Treponema Assay
Indications for Use: The LIAISON® Treponema Assay and the LIAISON® Treponema Serum Controls uses chemiluminescence immunoassay (CLIA) technology for the qualitative detection of total antibodies of any class (IqG/IgM) directed against Treponema pallidum in human serum. The presence of antibodies to Treponema pallidum specific antigen, in conjunction with nontreponemal laboratory tests and clinical findings, may aid in the diagnosis of syphilis infection. The LIAISON® Treponema Assay is not intended for use in the screening of blood or plasma donors.
Prescription Use: X (Part 21 CFR 801 Subpart D) AND/OR
Over-the-Counter Use: (Part 21 CFR 807 Subpart C)
(PLEASE DO NOT WRITE BELOW THIS LINE – CONTINUE ON ANOTHER PAGE IF NEEDED)
Concurrence of CDRH, Office of Device Evaluation
Luddite Park
Division Sign-On
Office of in Vitro Diagnosuc Device Fivaluation and Safer
Section 4
Page 4 - 1
§ 866.3830
Treponema pallidum treponemal test reagents.(a)
Identification. Treponema pallidum treponemal test reagents are devices that consist of the antigens, antisera and all control reagents (standardized reagents with which test results are compared) which are derived from treponemal sources and that are used in the fluorescent treponemal antibody absorption test (FTA-ABS), theTreponema pallidum immobilization test (T.P.I.), and other treponemal tests used to identify antibodies toTreponema pallidum directly from infecting treponemal organisms in serum. The identification aids in the diagnosis of syphilis caused by bacteria belonging to the genusTreponema and provides epidemiological information on syphilis.(b)
Classification. Class II (performance standards).