IMX SELECT CHLAMYDIA

K936054 · Abbott Laboratories · LJC · May 30, 1996 · Microbiology

Device Facts

• Record ID: K936054
• Device Name: IMX SELECT CHLAMYDIA
• Applicant: Abbott Laboratories
• Product Code: LJC · Microbiology
• Decision Date: May 30, 1996
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 866.3120
• Device Class: Class 1

Indications for Use

IMx SELECT Chlamydia is a Microparticle Enzyme Immunoassay (MEIA) for the qualitative detection of chlamydial LPS antigen and is indicated for use in testing female endocervical swab specimens, and male urethral swab specimens from symptomatic individuals to identify Chlamyia trachomatis. The IMx SELECT Chamydia Blocking Reagent may be used to verify the chlamydial specificity of the antigen detected.

Device Story

IMx SELECT Chlamydia is a Microparticle Enzyme Immunoassay (MEIA) for qualitative detection of chlamydial LPS antigen. Input: female endocervical or male urethral swab specimens. Principle: immunoassay detects chlamydial antigen; blocking reagent available for specificity verification. Output: qualitative test result. Used in clinical settings; performed by laboratory personnel. Provides rapid results (under 90 minutes) compared to 48-hour cell culture. Benefits: no special handling/storage required for specimen viability; detects chlamydia that may fail to grow in cell culture.

Clinical Evidence

Clinical study of 1,647 specimens from 6 clinics (STD, family planning, OB/GYN). Compared to cell culture with discordant resolution by DFA. Overall relative sensitivity 88.1% (95% CI 83.8-91.8%) and relative specificity 98.7% (95% CI 98.0-99.2%).

Technological Characteristics

Microparticle Enzyme Immunoassay (MEIA). Qualitative detection of chlamydial LPS antigen. In vitro diagnostic test.

Indications for Use

Indicated for symptomatic female patients (endocervical swab) and symptomatic male patients (urethral swab) to identify Chlamydia trachomatis infection.

Regulatory Classification

Identification

Chlamydia serological reagents are devices that consist of antigens and antisera used in serological tests to identify antibodies to chlamydia in serum. Additionally, some of these reagents consist of chlamydia antisera conjugated with a fluorescent dye used to identify chlamydia directly from clinical specimens or cultured isolates derived from clinical specimens. The identification aids in the diagnosis of disease caused by bacteria belonging to the genus Chlamydia and provides epidemiological information on these diseases. Chlamydia are the causative agents of psittacosis (a form of pneumonia), lymphogranuloma venereum (a venereal disease), and trachoma (a chronic disease of the eye and eyelid).

Reference Devices

• Isolation of C. trachomatis in tissue culture

Submission Summary (Full Text)

{0}

MAY 07 '96 03:02PM ADD REGULATORY AFFAIRS: DEVICES
P.20/22
K936054
MAY 30 1996

# Summary of Safety and Effectiveness Information Supporting a Substantially Equivalent Determination

The following information as presented in the 510(k) Premarket Notification for IMx SELECT Chlamydia constitutes data supporting a substantially equivalent determination:

IMx SELECT Chlamydia is a Microparticle Enzyme Immunoassay (MEIA) for the qualitative detection of chlamydial LPS antigen and is indicated for use in testing female endocervical swab specimens, and male urethral swab specimens from symptomatic individuals to identify *Chlamyia trachomatis*. The IMx SELECT Chamydia Blocking Reagent may be used to verify the chlamydial specificity of the antigen detected.

IMx SELECT Chlamydia is compared to isolation of *C. trachomatis* in tissue culture.

IMx SELECT Chlamydia and isolation of *C. trachomatis* in cell culture are substantially equivalent in that:

a. Both are intended for the detection of *C. trachomatis* infection.
b. Both are *in vitro* tests.

IMx SELECT Chlamydia and isolation of *C. trachomatis* in cell culture differ in that:

a. IMx SELECT Chlamydia measures *C. trachomatis* antigen and therefore detects chlamydia which fail to grow in cell culture.
b. IMx SELECT Chlamydia can be preformed in less than ninety minutes whereas cell culture techniques require a minimum of 48 hours before results are obtained.
c. IMx SELECT Chlamydia specimens do not require special handling and storage procedures to retain viability.

18

{1}

MAY 07 '96 03:02PM ADD REGULATORY AFFAIRS: DEVICES

P.21/22

A total of 1647 specimens were obtained from patients attending 6 different clinics, including sexually transmitted disease clinics, family planning clinics and OB/GYN clinics. The overall results, presented by symptomology and by prevalence and site, are shown in the tables below:

IMx SELECT Chlamydia Performance versus Culture with Discordant Resolution by DFA
Summary by Symptomology

| Population By Sample Type | No. | Pos | Pos | Pos | Neg | Neg | Total number of Samples | % Relative Sensitivity (95% CI) | % Relative Specificity (95% CI) | % Positive Predictive Value | % Negative Predictive Value |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| | Culture | Pos | Neg | Neg | Pos | Neg | | | | | |
| | DFA | NA | Pos | Neg | NA | NA | | | | | |
| FEMALE: Total | 134 | 15 | 14 | 15 | 282 | 1160 | 99.9 (149/164) (85.4-94.8) | 98.6 (982/998) (97.7-99.3) | 91.4 (149/163) | 98.5 (982/997) | |
| FEMALE: Symptomatic | 46 | 8 | 8 | 8 | 308 | 370 | 89.7 (82/58) (78.6-98.1) | 98.1 (980/312) (98.0-98.5) | 89.7 (82/58) | 98.1 (308/312) | |
| FEMALE: Asymptomatic | 44 | 5 | 8 | 8 | 390 | 453 | 89.1 (49/55) (77.8-93.3) | 98.0 (980/306) (98.1-98.1) | 88.0 (49/57) | 98.0 (300/306) | |
| FEMALE: Other* | 44 | 4 | 0 | 3 | 286 | 337 | 94.1 (49/61) (83.8-96.8) | 100.0 (286/296) (99.0-100.0) | 100.0 (48/48) | 99.0 (286/296) | |
| MALE: Symptomatic | 66 | 15 | 4 | 16 | 388 | 467 | 83.5 (51/67) (74.6-90.3) | 99.0 (380/390) (97.4-99.7) | 85.3 (51/66) | 98.0 (380/402) | |
| GRAND TOTAL | 203 | 30 | 18.6 | 21.1 | 1368 | 1647 | 88.1 (230/261) (83.8-91.8) | 98.7 (1008/1388) (98.0-99.2) | 82.7 (230/248) | 91.4 (1388/1388) | |

NA is not applicable. DFA testing not performed
CI is Confidence Intervals
* Routine prenatal screen or no specific information provided
23/28 culture positive, IMx negative specimens contain > 20 IFUs; 28/28 specimens have < 100 IFUs; 2 culture negative. IMx negative specimens were positive when tested by DFA.
8 Six specimens, negative by IMx SELECT Chlamydia but negative by culture/DFA, were tested by Polymerase Chain Reaction (PCR) technology. All six specimens were PCR positive. In addition, 7 out of 16 specimens tested with the IMx SELECT Chlamydia Blocking Reagent were verified as positive for chlamydial LPS antigen.

IMx SELECT Chlamydia Performance versus Culture with Discordant Resolution by DFA
Summary by Prevalence and Site

| Population By Sample Type | No. | Pos | Pos | Pos | Neg | Neg | Total number of Samples | % Relative Sensitivity (95% CI) | % Relative Specificity (95% CI) | % Prevalence |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| | Culture | Pos | Neg | Neg | Pos | Neg | | | | |
| | DFA | NA | Pos | Neg | NA | NA | | | | |
| FEMALE: Total | 134 | 15 | 14 | 15 | 282 | 1160 | 90.9 (149/164) (85.4-94.8) | 98.6 (982/998) (97.7-99.3) | 14.1 (164/1160) | |
| HIGH Prevalence | 95 | 7 | 6 | 6 | 461 | 575 | 94.4 (102/108) (88.3-97.9) | 98.7 (481/487) (97.2-99.6) | 18.8 (108/675) | |
| Site 1 | 54 | 3 | 6 | 3 | 238 | 304 | | | 19.7 (60/304) | |
| Site 1 (In-House Testing) | 41 | 4 | 0 | 3 | 223 | 271 | | | 17.7 (48/271) | |
| MID Prevalence | 35 | 6 | 8 | 9 | 359 | 447 | 84.3 (43/51) (71.4-93.0) | 98.0 (388/396) (98.1-99.1) | 11.4 (61/447) | |
| Site 2 | 6 | 1 | 2 | 4 | 140 | 152 | | | 6.6 (18/152) | |
| Site 3 | 30 | 7 | 6 | 4 | 248 | 295 | | | 13.6 (41/295) | |
| LOW Prevalence | 4 | 0 | 0 | 1 | 193 | 138 | 80.0 (4/5) (28.4-99.5) | 100.0 (133/132) (97.6-100.0) | 3.6 (8/198) | |
| Site 4 | 3 | 0 | 0 | 0 | 63 | 66 | | | 4.8 (3/66) | |
| Site 5 | 1 | 0 | 0 | 1 | 70 | 72 | | | 2.8 (2/72) | |
| MALE: Total | 68 | 15 | 4 | 16 | 388 | 467 | 83.6 (81/97) (74.6-90.3) | 99.0 (388/390) (97.4-99.7) | 19.9 (97/487) | |
| Site 3 | 39 | 7 | 2 | 13 | 238 | 299 | | | 19.7 (69/299) | |
| Site 3 (In-House Testing) | 23 | 6 | 2 | 3 | 107 | 141 | | | 22.7 (32/141) | |
| Site 6 | 4 | 2 | 0 | 0 | 41 | 47 | | | 12.6 (8/47) | |
| GRAND TOTAL | 200 | 30 | 18 | 31 | 1388 | 1647 | 88.1 (230/261) (83.8-91.8) | 98.7 (1008/1388) (98.0-99.2) | 16.9 (261/1647) | |

{2}

MAY 07 '96 03:03PM ADD REGULATORY AFFAIRS: DEVICES P.22/22

In conclusion, the IMx SELECT Chlamydia Assay is substantially equivalent to the isolation of *C. trachomatis* in cell culture for the detection of *C. trachomatis* antigens in endocervical and male urethral swab specimens.

Prepared and submitted May 7, 1996
Greg Murawski
847-937-0109
Abbott Laboratories
200 Abbott Park Road
Abbott Park, Ill. 60064-3537

20