TOXOPLASMA IGG IN-VITRO DIAGNOSTIC SYSTEM
Device Facts
| Record ID | K955760 |
|---|---|
| Device Name | TOXOPLASMA IGG IN-VITRO DIAGNOSTIC SYSTEM |
| Applicant | Bayer Corp. |
| Product Code | LGD · Microbiology |
| Decision Date | Aug 2, 1996 |
| Decision | SESE |
| Submission Type | Traditional |
| Regulation | 21 CFR 866.3780 |
| Device Class | Class 2 |
Intended Use
This in vitro diagnostic method in intended to quantitatively and qualitatively measure Toxoplasma IgG in human serum on the Technicon Immuno 1® System. Measurements of Toxoplasma IgG are designed to aid in the determination of serological status by detecting IgG class antibodies to Toxoplasma gondii in human sera. The Technicon Immuno 1 Toxoplasma IgG method is not intended for use in screening blood or plasma donors. The method is intended for in vitro diagnostic use only on the Technicon IMMUNO 1® system.
Device Story
The Technicon Immuno 1 Toxoplasma IgG method is an in vitro diagnostic assay performed on the Technicon Immuno 1 System. It utilizes human serum samples to detect IgG class antibodies to Toxoplasma gondii. The system processes samples to provide quantitative and qualitative results, aiding clinicians in assessing a patient's serological status. The device is intended for use in clinical laboratory settings. Healthcare providers use the output to determine the presence of IgG antibodies, which informs clinical decision-making regarding toxoplasmosis. The assay is calibrated against the WHO anti-Toxoplasma Serum International Standard (TOXS-60).
Clinical Evidence
Clinical performance evaluated at two sites (University of Texas Medical Branch and San Francisco General Hospital) comparing the Immuno 1 assay to the Abbott IMx assay. Combined clinical data (n=585-598) showed overall agreement ranging from 94.0% to 96.8% depending on reagent lot and resolution method. Sensitivity and specificity were calculated relative to the predicate and IFA-resolved samples. ROC analysis yielded AUC values between 0.967 and 0.990. Interference studies confirmed no significant impact from hemolysis, lipemia, icterus, or common viral/rheumatoid antibodies.
Technological Characteristics
In vitro diagnostic immunoassay for use on the Technicon Immuno 1 System. Calibrated against WHO anti-Toxoplasma Serum International Standard (TOXS-60). Quantitative range 12-300 IU/mL. Employs automated processing on the Immuno 1 platform. No specific materials of construction or software algorithm architecture details provided beyond standard clinical chemistry analyzer functionality.
Indications for Use
Indicated for the quantitative and qualitative measurement of Toxoplasma IgG in human serum to aid in determining serological status regarding Toxoplasma gondii infection. Not for blood or plasma donor screening.
Regulatory Classification
Identification
Toxoplasma gondii serological reagents are devices that consist of antigens and antisera used in serological tests to identify antibodies to Toxoplasma gondii in serum. Additionally, some of these reagents consist of antisera conjugated with a fluorescent dye (immunofluorescent reagents) used to identify Toxoplasma gondii from clinical specimens. The identification aids in the diagnosis of toxoplasmosis caused by the parasitic protozoan Toxoplasma gondii and provides epidemiological information on this disease. Congenital toxoplasmosis is characterized by lesions of the central nervous system, which if undetected and untreated may lead to brain defects, blindness, and death of an unborn fetus. The disease is characterized in children by inflammation of the brain and spinal cord.
Predicate Devices
- Abbott IMx Toxoplasma IgG assay
Reference Devices
- Gull Laboratories Toxo IgG Indirect Fluorescent Antibody Test
- Sanofi Platelia Toxoplasma IgG
Related Devices
- K080869 — ACCESS TOXO IGG, ACCESS TOXO IGG CALIBRATORS AND ACCESS TOXO IGG QC · Beckman Coulter, Inc. · May 23, 2008
- K971441 — QUANTA LITE TOXOPLASMA IGG · Inova Diagnostics, Inc. · Dec 2, 1997
- K954575 — AXSYM TOXO IGG ANTIBODY ASSAY · Abbott Laboratories · Aug 16, 1996
- K981498 — IS-TOXOPLASMA IGG TEST SYSTEM · Diamedix Corp. · Aug 21, 1998
- K012183 — BAYER DIAGNOSTICS ADVIA CENTAUR TOXOPLASMA IGG ASSAY · Bayer Diagnostics Corp. · Dec 27, 2001
Submission Summary (Full Text)
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K955760
Enclosure 2
AUG - 2 1996
# SUMMARY OF SAFETY AND EFFECTIVENESS FOR THE TECHNICON TOXOPLASMA IgG METHOD FOR THE IMMUNO 1® SYSTEM
Listed below are comparisons of the performance between the IMMUNO 1® Toxoplasma IgG method (Attachment 1) and a similar device that was granted FDA determination of substantial equivalence: the Abbott IMx Toxoplasma IgG assay (Attachment 2). The comparative data with the Abbott IMx assay was collected at two outside clinical trial sites: University of Texas Medical Branch, Laboratory Medical Clinical Chemistry, Galveston, Texas and San Francisco General Hospital Clinical Laboratories, San Francisco, California. Two lots of IMMUNO 1® Toxoplasma IgG reagents were evaluated at each clinical site. IFA discrepant sample testing was done by BBI - North American Clinical Laboratories in New Britain, CT using Gull Laboratories Toxo IgG Indirect Fluorescent Antibody Test (Attachment 3). Discrepant samples for IFA testing were shipped directly to BBI from the clinical site.
## INTENDED USE
This in vitro diagnostic method in intended to quantitatively and qualitatively measure Toxoplasma IgG in human serum on the Technicon Immuno 1® System. Measurements of Toxoplasma IgG are designed to aid in the determination of serological status by detecting IgG class antibodies to Toxoplasma gondii in human sera. The Technicon Immuno 1 Toxoplasma IgG method is not intended for use in screening blood or plasma donors. The method is intended for in vitro diagnostic use only on the Technicon IMMUNO 1® system.
## CHARACTERISTICS
The Technicon IMMUNO 1® Toxoplasma IgG is calibrated with six calibrators having values of 0, 10, 20, 50, 100, 300 IU/mL and traceable to the WHO anti-Toxoplasma Serum International Standard (TOXS-60) described in Attachment 5. Agreement between Toxoplasma IgG SETpoint Calibrators and the WHO TOXS-60 Standard is shown in Figure 1.
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Figure 1. Correlation between WHO Second International Toxoplasma Standard Preparation and Immuno 1 Toxoplasma IgG method calibrated with the Technicon SETpoint Toxoplasma IgG Calibrators.
Linear regression analysis yielded the following results:
| Y = 0.905 X + 1.618 |
| --- |
| R² = 0.9998 |
| 95% CL intercept = ± 2.44 |
| 95% CL slope = ± 0.019 |
# METHOD COMPARISONS
Comparative results to the Abbott IMx were collected from two clinical trial sites each using two lots of Immuno 1 Toxoplasma IgG reagents. The clinical trial protocol and report are available in attachments contained in the 510(k). Resolution of discrepant results was done by IFA analysis using exclusion.
Samples with Immuno 1 values <12 IU/mL are considered negative for the presence of toxoplasma IgG antibodies. Samples with Immuno 1 values ≥12 IU/mL are considered positive for the presence IgG antibodies to toxoplasma gondii. The IMx Toxoplasma IgG method uses 6 IU/mL as the cut-off.
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# Clinical Sample Characterization
The distribution of Immuno 1 Toxoplasma IgG results within two populations consisting of 223 prenatal specimens submitted for routine Toxoplasma IgG testing at clinical site 1 and 225 specimens selected at random from routine laboratory specimens at clinical site 2 is shown in Table 1. A seronegative rate of 78% and 79.1 is observed at site 1 and site 2, respectively. These results are consistent with a seronegativity rate of 30% to 80% in the US population, Anderson SE and Remington JS: The diagnosis of toxoplasmosis. Southern Med Jour 68:1433-1443 (1975).
TABLE 1: DISTRIBUTION OF SERUM TECHNICON IMMUNO 1 TOXOPLASMA IgG VALUES IN PRENATAL AND HOSPITAL SPECIMENS
| TECHNICON IMMUNO 1 TOXOPLASMA IgG (IU/mL) | PRENATAL SPECIMENS CLINICAL SITE 1 | | HOSPITAL SPECIMENS CLINICAL SITE 2 | |
| --- | --- | --- | --- | --- |
| | NO. OF SPECIMENS | % OF TOTAL | NO. OF SPECIMENS | % OF TOTAL |
| < 3 | 129 | 57.8 | 69 | 30.7 |
| 3 - 6 | 25 | 11.2 | 74 | 32.9 |
| 6 - 9 | 12 | 5.4 | 25 | 11.1 |
| 9 - 12 | 8 | 3.6 | 10 | 4.4 |
| 12 - 20 | 3 | 1.3 | 7 | 3.1 |
| 20 - 50 | 10 | 4.5 | 10 | 4.4 |
| 50 - 100 | 20 | 9.0 | 8 | 3.6 |
| 100 - 200 | 8 | 3.6 | 12 | 5.3 |
| 200 - 300 | 5 | 2.2 | 4 | 1.8 |
| > 300 | 3 | 1.3 | 6 | 2.7 |
| TOTAL | 223 | 100 | 225 | 100 |
In addition to the site supplied specimens, each site augmented their study with an additional 75 supplemental serum specimens unique to each site. The supplemental specimens were masked having both negative and positive samples and were supplied frozen. The additional samples were necessary in order to raise the number of positive specimens analyzed at each site. Of the 298 sera analyzed at clinical site 1, 110 had been frozen prior to analysis. Similarly, 117 out of the 300 sera analyzed at clinical site 2 had been frozen prior to analysis. The unfrozen specimens were fresh or had been stored at 2°C to 8°C for less than 1 week after collection.
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# Sensitivity, Specificity and Overall Agreement
Sensitivity and specificity results are presented in Table 2 relative to the Abbott IMx Toxoplasma IgG method. Single replicate results for both the Immuno 1 and Abbott IMx assay were collected for comparison at the clinical sites. Discrepant samples at clinical site 2 were subsequently tested twice on both instruments and classified as either positive or negative based on two out of three results. Additional masked samples from Boston Biomedica Inc. were supplied to both clinical trial sites (see Clinical Trial Protocol and Report for additional information) in order to increase the number of Toxoplasma IgG positives.
Table 2. Immuno 1 Toxoplasma IgG Sensitivity and Specificity relative to the Abbott IMx Toxoplasma IgG assay. Site 1 is the University of Texas Medical Branch in Galvelston and Site 2 is San Francisco General Hospital. The cut-off for the Immuno 1 and IMx Toxoplasma IgG assays is 12 IU/mL and 6 IU/mL, respectively. Resolution by IFA excludes a discrepant result if agreement between IFA and Immuno 1 is found. The 95% confidence limits for sensitivity, specificity and overall agreement are calculated using exact binomial percentiles according to Blyth, C.R., Approximate Binomial Confidence Limits, J Amer. Stat. Assoc, 81:843-855 (1986).
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DEC 17 '95 01:16PM PARTY INMUNOL P106
Site 1 University of Texas Medical Branch
| Immuno 1 Rgts & Sample Description | Number of Results by IMx Classification | No. of Immuno 1 Results in Agreement with IMx Classification | Sensitivity, Specificity or Overall Agreement (%) | 95% Confidence Limits (%) |
| --- | --- | --- | --- | --- |
| Immuno 1 Lot 1 Rgts | | | | |
| Site 1 Supplied | | | | |
| Sensitivity | 49 | 45 | 91.8 | 80.4 - 97.7 |
| Specificity | 174 | 170 | 97.7 | 94.2 - 99.4 |
| Overall Agreement | 223 | 215 | 96.4 | 93.1 - 98.4 |
| Supplemental Samples | | | | |
| Sensitivity | 55 | 54 | 98.2 | 90.3 - 100 |
| Specificity | 20 | 18 | 90.0 | 68.3 - 98.8 |
| Overall Agreement | 75 | 72 | 96.0 | 88.8 - 99.2 |
| Combined | | | | |
| Sensitivity | 104 | 99 | 95.2 | 89.1 - 98.4 |
| Specificity | 194 | 188 | 96.9 | 93.4 - 98.9 |
| Overall Agreement | 298 | 287 | 96.3 | 93.5 - 98.1 |
| Immuno 1 Lot 2 Rgts | | | | |
| Site 1 Supplied | | | | |
| Sensitivity | 49 | 46 | 93.9 | 83.1 - 98.7 |
| Specificity | 174 | 169 | 97.1 | 93.4 - 99.1 |
| Overall Agreement | 223 | 215 | 96.4 | 93.1 - 98.4 |
| Supplemental Samples | | | | |
| Sensitivity | 55 | 53 | 96.4 | 87.5 - 99.6 |
| Specificity | 20 | 18 | 90.0 | 68.3 - 98.8 |
| Overall Agreement | 75 | 71 | 94.7 | 86.9 - 98.5 |
| Combined | | | | |
| Sensitivity | 104 | 99 | 95.2 | 89.1 - 98.4 |
| Specificity | 194 | 187 | 96.4 | 92.7 - 98.5 |
| Overall Agreement | 298 | 286 | 96.0 | 93.1 - 97.9 |
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Site 1 University of Texas Medical Branch - IFA Resolved
| Immuno 1 Rgts & Sample Description | Number of Resolved Results | No. of Immuno 1 Results in Agreement with Resolved Results | Sensitivity, Specificity or Overall Agreement (%) | 95% Confidence Limits (%) |
| --- | --- | --- | --- | --- |
| Immuno 1 Lot 1 Rgts | | | | |
| Site 1 Supplied | | | | |
| Sensitivity | 49 | 45 | 91.8 | 80.4 - 97.7 |
| Specificity | 172 | 170 | 98.8 | 95.9 - 99.9 |
| Overall Agreement | 221 | 215 | 97.3 | 94.2 - 99.0 |
| Supplemental Samples | | | | |
| Sensitivity | 54 | 54 | 100 | 93.4 - 100 |
| Specificity | 19 | 18 | 94.7 | 74.0 - 99.9 |
| Overall Agreement | 73 | 72 | 98.6 | 92.6 - 100 |
| Combined | | | | |
| Sensitivity | 103 | 99 | 96.1 | 90.4 - 98.9 |
| Specificity | 191 | 188 | 98.4 | 95.5 - 99.7 |
| Overall Agreement | 294 | 287 | 97.6 | 95.2 - 99.0 |
| Immuno 1 Lot 2 Rgts | | | | |
| Site 1 Supplied | | | | |
| Sensitivity | 49 | 46 | 93.9 | 83.1 - 98.7 |
| Specificity | 172 | 169 | 98.3 | 95.0 - 99.6 |
| Overall Agreement | 221 | 215 | 97.3 | 94.2 - 99.0 |
| Supplemental Samples | | | | |
| Sensitivity | 54 | 53 | 98.2 | 90.1 - 100 |
| Specificity | 19 | 18 | 94.7 | 74.0 - 99.9 |
| Overall Agreement | 73 | 71 | 97.3 | 90.5 - 99.7 |
| Combined | | | | |
| Sensitivity | 103 | 99 | 96.1 | 90.4 - 98.9 |
| Specificity | 191 | 187 | 97.9 | 94.7 - 99.4 |
| Overall Agreement | 294 | 286 | 97.3 | 94.7 - 98.8 |
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Site 2 San Francisco General Hospital
| Immuno 1 Rgts & Sample Description | Number of Results by IMx Classification | No. of Immuno 1 Results in Agreement with IMx Classification | Sensitivity, Specificity or Overall Agreement (%) | 95% Confidence Limits (%) |
| --- | --- | --- | --- | --- |
| Immuno 1 Lot 1 Rgts | | | | |
| Site 2 Supplied | | | | |
| Sensitivity | 43 | 35 | 81.4 | 66.6 - 91.6 |
| Specificity | 182 | 170 | 93.4 | 88.8 - 96.5 |
| Overall Agreement | 225 | 205 | 91.1 | 86.6 - 94.5 |
| Supplemental Samples | | | | |
| Sensitivity | 48 | 48 | 100 | 92.6 - 100 |
| Specificity | 27 | 26 | 96.3 | 81.0 - 99.9 |
| Overall Agreement | 75 | 74 | 98.7 | 92.8 - 100 |
| Combined | | | | |
| Sensitivity | 91 | 83 | 91.2 | 83.4 - 96.1 |
| Specificity | 209 | 196 | 93.8 | 89.6 - 96.6 |
| Overall Agreement | 300 | 279 | 93.0 | 89.5 - 95.6 |
| Immuno 1 Lot 2 Rgts | | | | |
| Site 2 Supplied | | | | |
| Sensitivity | 44 | 33 | 75.0 | 59.7 - 86.8 |
| Specificity | 181 | 170 | 93.9 | 89.4 - 96.9 |
| Overall Agreement | 225 | 203 | 90.2 | 85.6 - 93.8 |
| Supplemental Samples | | | | |
| Sensitivity | 48 | 47 | 97.9 | 88.9 - 99.9 |
| Specificity | 27 | 26 | 96.3 | 81.0 - 99.9 |
| Overall Agreement | 75 | 73 | 97.3 | 90.7 - 99.7 |
| Combined | | | | |
| Sensitivity | 92 | 80 | 87.0 | 78.3 - 93.1 |
| Specificity | 208 | 196 | 94.2 | 90.1 - 97.0 |
| Overall Agreement | 300 | 276 | 92.0 | 88.3 - 94.8 |
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Site 2 San Francisco General Hospital - IFA Resolved
| Immuno 1 Rgts & Sample Description | Number of Resolved Results | No. of Immuno 1 Results in Agreement with Resolved Results | Sensitivity, Specificity or Overall Agreement (%) | 95% Confidence Limits (%) |
| --- | --- | --- | --- | --- |
| Immuno 1 Lot 1 Rgts | | | | |
| Site 2 Supplied | | | | |
| Sensitivity | 43 | 35 | 81.4 | 66.6 - 91.6 |
| Specificity | 182 | 170 | 93.4 | 88.8 - 96.5 |
| Overall Agreement | 225 | 205 | 91.1 | 86.6 - 94.5 |
| Supplemental Samples | | | | |
| Sensitivity | 48 | 48 | 100 | 92.6 - 100 |
| Specificity | 27 | 26 | 96.3 | 81.0 - 99.9 |
| Overall Agreement | 75 | 74 | 98.7 | 92.8 - 100 |
| Combined | | | | |
| Sensitivity | 85 | 83 | 97.6 | 91.8 - 99.7 |
| Specificity | 206 | 196 | 95.1 | 91.3 - 97.6 |
| Overall Agreement | 291 | 279 | 95.9 | 92.9 - 97.9 |
| Immuno 1 Lot 2 Rgts | | | | |
| Site 2 Supplied | | | | |
| Sensitivity | 44 | 33 | 75.0 | 59.7 - 86.8 |
| Specificity | 181 | 170 | 93.9 | 89.4 - 96.9 |
| Overall Agreement | 225 | 203 | 90.2 | 85.6 - 93.8 |
| Supplemental Samples | | | | |
| Sensitivity | 48 | 47 | 97.9 | 88.9 - 99.9 |
| Specificity | 27 | 26 | 96.3 | 81.0 - 99.9 |
| Overall Agreement | 75 | 74 | 98.7 | 92.8 - 100 |
| Combined | | | | |
| Sensitivity | 85 | 80 | 94.1 | 86.8 - 98.1 |
| Specificity | 206 | 196 | 95.1 | 91.3 - 97.6 |
| Overall Agreement | 291 | 276 | 94.8 | 91.6 - 97.1 |
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# Combined Clinical Site 1 & 2 Results: Unresolved Results
| Immuno 1 Rgts & Sample Description | Number of Results by IMx Classification | No. of Immuno 1 Results in Agreement with IMx Classification | Sensitivity, Specificity or Overall Agreement (%) | 95% Confidence Limits (%) |
| --- | --- | --- | --- | --- |
| Immuno 1 Lot 1 Rgts | | | | |
| All Specimens | | | | |
| Sensitivity | 195 | 182 | 93.3 | 88.9 - 96.4 |
| Specificity | 403 | 384 | 95.3 | 92.7 - 97.1 |
| Overall Agreement | 598 | 566 | 94.6 | 92.5 - 96.3 |
| Immuno 1 Lot 2 Rgts | | | | |
| All Specimens | | | | |
| Sensitivity | 196 | 179 | 91.3 | 86.5 - 94.9 |
| Specificity | 402 | 383 | 95.3 | 92.7 - 97.1 |
| Overall Agreement | 598 | 562 | 94.0 | 91.8 - 95.7 |
# Combined Clinical Site 1 & 2 Results: IFA Resolved
| Immuno 1 Rgts & Sample Description | Number of Resolved Results | No. of Immuno 1 Results in Agreement with Resolved Results | Sensitivity, Specificity or Overall Agreement (%) | 95% Confidence Limits (%) |
| --- | --- | --- | --- | --- |
| Immuno 1 Lot 1 Rgts | | | | |
| All Specimens | | | | |
| Sensitivity | 188 | 182 | 96.8 | 93.2 - 98.8 |
| Specificity | 397 | 384 | 96.7 | 94.5 - 98.2 |
| Overall Agreement | 585 | 566 | 96.8 | 95.0 - 98.0 |
| Immuno 1 Lot 2 Rgts | | | | |
| All Specimens | | | | |
| Sensitivity | 188 | 179 | 95.2 | 91.1 - 97.8 |
| Specificity | 397 | 383 | 96.5 | 94.2 - 98.1 |
| Overall Agreement | 585 | 562 | 96.1 | 94.2 - 97.5 |
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Table 3: IFA RESULTS ON DISCREPANT SAMPLES
| STUDY LOCATION | COMPARATIVE METHOD | IMMUNO 1 DISCREPANCIES | DISCREPANT RESULTS | IFA POSITIVE | IFA NEGATIVE |
| --- | --- | --- | --- | --- | --- |
| Clinical Site 1
Lot 1 Rgts | Abbott IMx | False Negative | 5 | 4 | 1 |
| | | False Positive | 6 | 3 | 3 |
| Lot 2 Rgts | Abbott IMx | False Negative | 5 | 4 | 1 |
| | | False Positive | 7 | 3 | 4 |
| Clinical Site 2
Lot 1 Rgts | Abbott IMx | False Negative | 8 | 2 | 6 |
| | | False Positive | 13 | 3 | 10 |
| Lot 2 Rgts | Abbott IMx | False Negative | 12 | 5 | 7 |
| | | False Positive | 12 | 2 | 10 |
Receiver-Operating Characteristic (ROC) Analysis
The area under the ROC plots is used as an estimate of the diagnostic accuracy of the Immuno 1 Toxoplasma IgG assay relative to the IMx Toxoplasma IgG assay. ROC plots are shown in Figure 2 a-d for both TXG and TYG Immuno 1 Toxoplasma IgG reagent lots at Univ of Texas Medical Branch and San Francisco General Hospital.
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Figure 2. ROC Plot analysis of comparative Immuno 1 and IMx Toxoplasma IgG methods.
(a) ROC Plot. Immuno 1 vs IMx. University of Texas Medical Branch employing TXG Lot 1 Immuno 1 Toxoplasma IgG Reagents. (Area = 0.990)
(b) ROC Plot. Immuno 1 vs IMx. University of Texas Medical Branch employing Lot 2 Immuno 1 Toxoplasma IgG Reagents. (Area = 0.989)
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ROC Plot: IMMUNO1 vs IMx TOXOPLASMA IgG Rgt Lot 1 SAN FRANCISCO GEN HOSPITAL
(1 - specificity)
(c). ROC Plot. Immuno 1 vs IMx. San Francisco General Hospital employing Lot 1 Immuno 1 Toxoplasma IgG Reagents. (Area = 0.967)
(d) ROC Plot. Immuno 1 vs IMx. San Francisco General Hospital employing Lot 2 Immuno 1 Toxoplasma IgG Reagents. (Area = 0.968)
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Table 4. ROC Plot Areas for Immuno1 relative to the IMx Toxoplasma IgG Method
| CLINICAL SITE | Immuno1 Reagent Lot | Comparative Method | ROC Area |
| --- | --- | --- | --- |
| Univ of Texas MB | Lot 1 | IMx | 0.990 |
| | Lot 2 | IMx | 0.989 |
| San Francisco GH | Lot 1 | IMx | 0.967 |
| | Lot 2 | IMx | 0.968 |
| Combined Clinical Sites | Lot 1 | IMx | 0.980 |
| | Lot 2 | IMx | 0.980 |
Comparison of Immuno 1 Toxoplasma IgG Reagent Lots
The clinical results obtained with both Lots of Immuno 1 Toxoplasma IgG Reagents evaluated at the University of Texas MB and San Francisco General Hospital were compared both with respect to classification and correlation of clinical values.
Table 5. Reproducibility of results between Immuno 1 Toxoplasma IgG Reagent Lots at Univ. of Texas and San Francisco General Hospital
| CLINICAL TRIAL SITE | | LOT 2 REAGENTS | | OVERALL AGREEMENT (%) |
| --- | --- | --- | --- | --- |
| Univ. of Texas MB LOT 1 REAGENTS | Pos Neg | Pos 104 | Neg 1 | 99.0 |
| | | 2 | 191 | |
| | | | | |
| San Francisco GH LOT 1 REAGENTS | Pos Neg | 91 | 4 | 98.7 |
| | | 0 | 205 | |
Regression analysis of the results between reagent lots is given in Table 6. Correlation plots are presented in Figure 3 a&b.
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Table 6. Regression analysis of Immuno 1 results between reagent lots. Results above 300 IU/mL omitted.
| Site | Immuno 1 Rubella IgG Reagent Lot | Y (intercept) ± 95% C.L. | Slope ± 95% C.L. | R value |
| --- | --- | --- | --- | --- |
| Univ. of Texas MB | Lot 1 vs Lot 2 | 0.59 ± 2.08 | 0.973 ± 0.029 | 0.969 |
| San Francisco GH | Lot 1 vs Lot 2 | 2.70 ± 2.20 | 0.993 ± 0.034 | 0.960 |
Figure 3. Correlation plots between Immuno 1 Toxoplasma IgG reagent lots 1 & 2. Results > 300 IU/mL are not shown.
(a) Immuno 1 IgG reagent Lot 1 versus Lot 2. Data was collected at the University of Texas Medical Branch at Galvelston.
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(b) Toxoplasma IgG reagent Lot 1 versus Lot 2. Data was collected at the San Francisco General Hospital.
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# Comparison of Immuno1 Toxoplasma IgG to IFA
The histogram in Figure 4 show the comparison between IFA and Immuno 1 Toxoplasma IgG results on 35 human sera 22 of which are negative. An IFA titre less than 16 is considered negative. IFA testing was performed by Boston Biomedica using Gull Laboratories IFA method. As expected the magnitude of the reported IgG level cannot be correlated to an endpoint titer.
IMMUNO 1 vs IFA Toxoplasma IgG
Figure 4. Comparison of Immuno 1 Toxoplasma IgG and IFA results. Twenty-two of the 35 specimens shown are have IFA negative having titers less than 1:16. These twenty-one of the IFA negative samples have Immuno 1 values less than or equal to $1.0\mathrm{IU/mL}$ with one result having an Immuno 1 value of $5\mathrm{IU/mL}$.
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# Linearity
The linearity of the assay over the claimed range between 12 and 300 IU/mL is demonstrated in the following experiment. Eight patient samples and the were assayed in triplicate, diluted independently in Immuno 1 Sample Diluent B and measured in 2 separate runs. Fresh dilutions of 1:5 and 1:10 were made before each run. Linear regression analysis of the results are presented in Table 7 along with the 95% confidence intervals for the y-intercept and the slope.
Table 7. Linearity study.
| Sample | Dil Factor | Run 1 Rep 1 | Run 1 Rep 2 | Run 2 Rep 1 | Run 2 Rep 2 | Total CV | Y - INTER ±95% C. L. | SLOPE ±95% C. L. | R value |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Pat 1 | 1 | 222 | 215 | 198 | 207 | 4.9 | -12.0 ± 5.5 | 222.4 ± 9.3 | 0.998 |
| " | 5 | 31 | 32 | 30 | 32 | 3.1 | | | |
| " | 10 | 12 | 12 | 10 | 11 | 8.5 | | | |
| Pat 2 | 1 | 208 | 208 | 192 | 208 | 3.9 | -8.8 ± 4.3 | 212.8 ± 7.3 | 0.999 |
| " | 5 | 35 | 35 | 32 | 33 | 4.4 | | | |
| " | 10 | 13 | 15 | 10 | 12 | 16.7 | | | |
| Pat 3 | 1 | 154 | 152 | 145 | 122 | 10.2 | -7.7 ± 7.7 | 150.9 ± 13.0 | 0.993 |
| " | 5 | 23 | 23 | 20 | 21 | 6.9 | | | |
| " | 10 | 8 | 8.6 | 7.5 | 8.1 | 5.6 | | | |
| Pat 4 | 1 | 195 | 178 | 179 | 167 | 6.4 | -7.0 ± 6.0 | 186.7 ± 10.2 | 0.997 |
| " | 5 | 31 | 29 | 31 | 31 | 3.3 | | | |
| " | 10 | 12 | 12 | 10.3 | 12 | 7.3 | | | |
| Pat 5 | 1 | 232 | 229 | 208 | 212 | 5.5 | -12.5 ± 6.5 | 232.6 ± 11.0 | 0.998 |
| " | 5 | 31 | 31 | 32 | 34 | 4.4 | | | |
| " | 10 | 13 | 14 | 11 | 12 | 10.3 | | | |
| Pat 6 | 1 | 171 | 166 | 160 | 160 | 3.2 | -9.0 ± 3.0 | 173.1 ± 5.0 | 0.999 |
| " | 5 | 24 | 25 | 24 | 25 | 2.4 | | | |
| " | 10 | 11 | 8.6 | 8.6 | 9 | 12.4 | | | |
| Pat 7 | 1 | 316 | 302 | 295 | 307 | 2.9 | -5.1 ± 5.1 | 310.1 ± 8.7 | 0.999 |
| " | 5 | 56 | 58 | 58 | 59 | 2.2 | | | |
| " | 10 | 26 | 20 | 25 | 30 | 16.3 | | | |
| Pat 8 | 1 | 167 | 158 | 176 | 180 | 5.8 | -10.9 ± 5.4 | 181.0 ± 9.1 | 0.997 |
| " | 5 | 24 | 22 | 22 | 25 | 6.5 | | | |
| " | 10 | 8.7 | 9.5 | 8.5 | 9.1 | 5.0 | | | |
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# INTERFERENCES
The use of hemolyzed (up to 1000 mg/dL of hemoglobin), lipemic (up to 900 mg/dL of triglycerides) or icteric (up to 25 mg/dL of total bilirubin) samples have no clinically significant effect on method performance, Table 8. Patient samples containing rheumatoid factor, antibodies to Epstein-Barr virus, cytomegalovirus, varicella zoster virus, Herpes Type I virus, Herpes Type II virus and rubeola (measles) virus produced no false positive results in comparison to the Sanofi Platelia method.
## TABLE 8 POTENTIAL CHEMICAL INTERFERENCES
### CHOLESTEROL
| mg/dL | IU/mL
TOXO IgG | % CV | % BIAS |
| --- | --- | --- | --- |
| 50 | 13.2 | 3.9 | 6.5 |
| 0 | 12.4 | 9.0 | |
| 100 | 10.4 | 5.7 | -9.6 |
| 0 | 11.4 | 2.1 | |
| 300 | 7.9 | 2.6 | -2.5 |
| 0 | 8.1 | 6.5 | |
| 400 | 6.5 | 2.6 | -9.7 |
| 0 | 7.2 | .9 | |
### TRIGLYCERIDE
| mg/dL | IU/mL
TOXO IgG | % BIAS |
| --- | --- | --- |
| 226 | 11.2 | 4.7 |
| 0 | 10.7 | |
| 470 | 9.1 | 2.2 |
| 0 | 8.9 | |
| 1180 | 5.9 | 0 |
| 0 | 5.9 | |
### HEMOGLOBIN
| mg/dL | IU/mL
TOXO IgG | % CV | % BIAS |
| --- | --- | --- | --- |
| 250 | 13.1 | 3.5 | -10.9 |
| 0 | 14.7 | 1.4 | |
| 500 | 13.1 | 4 | -3.7 |
| 0 | 13.6 | 6.3 | |
| 750 | 12.5 | 7.2 | 5.9 |
| 0 | 11.8 | 7.8 | |
| 1000 | 10.3 | 0.9 | -11.2 |
| 0 | 7.8 | 11.6 | |
### BILIRUBIN
| mg/dL | IU/mL
TOXO IgG | % CV | % BIAS |
| --- | --- | --- | --- |
| 6.2 | 13.2 | 7.2 | 7.3 |
| 0 | 12.3 | 1.8 | |
| 12.5 | 10.5 | 1.9 | 7.1 |
| 0 | 9.8 | 2.1 | |
| 18.8 | 9.8 | 4.6 | 0 |
| 0 | 9.8 | 3.8 | |
| 25 | 10 | 2.4 | 3.1 |
| 0 | 9.7 | 2.7 | |
{18}
# Potential Immunological Interferences
A panel of 60 human clinical samples positive for a variety of disease states and potentially interfering IgG antibodies was obtained from Boston Biomedica, Inc. Boston Biomedica COA (Attachment 12) for the specimens identifies the commercial assay kits used to identify the samples along with the test and control results. The samples were analyzed for discrepancies between Immuno 1 and Platelia Toxoplasma IgG results. As shown in Table 9 correlation between the two method classifications is good. Two samples results are discrepant between the Immuno 1 and Platelia. These samples are weakly positive by the Immuno 1 at 15.7 and 19.4 IU/mL with corresponding Platelia values of 4.7 and 4.9 IU/mL. The cut-off for Platelia is 6 IU/mL and 12 IU/mL for the Immuno 1 method. These are not considered significantly different results.
Table 9 Interference study results.
| Antibody | Sample ID | Platelia Toxoplasma IgG | | Immuno1 Toxoplasma IgG | |
| --- | --- | --- | --- | --- | --- |
| | | IU/mL | Result | IU/mL | Result |
| anti-EBV Pos | AT4-2707-0139 | 4.7 | NEG | 15.7 | POS |
| * | AT4-2707-0144 | 107.6 | POS | 150 | POS |
| * | AT4-2707-0146 | 0.0 | NEG | 3 | NEG |
| * | AT4-2707-0156 | 0.0 | NEG | 0 | NEG |
| * | AT4-2707-0179 | 0.3 | NEG | 4 | NEG |
| * | AT4-2707-0184 | 2.1 | NEG | 2 | NEG |
| * | AT4-2707-0209 | 0.0 | NEG | 1 | NEG |
| * | AT4-2707-0216 | 0.8 | NEG | 1 | NEG |
| * | DL4-3508-0138 | 23.7 | POS | 26 | POS |
| * | DL4-3508-0149 | 0.9 | NEG | 1 | NEG |
| anti-CMV IgG | DL2-3501-0010 | 0.0 | NEG | 4 | NEG |
| * | DL2-3501-0023 | 0.0 | NEG | 2 | NEG |
| * | DL2-3501-0026 | 0.0 | NEG | 7 | NEG |
| * | DL2-3501-0034 | 0.8 | NEG | 5 | NEG |
| * | DL2-3501-0049 | 0.0 | NEG | 3 | NEG |
| * | DL2-3501-0064 | 0.0 | NEG | 1 | NEG |
| * | DL2-3501-0067 | 0.0 | NEG | 2 | NEG |
| * | DL2-3501-0077 | 359.6 | POS | 453 | POS |
| * | DL2-3501-0095 | 1.1 | NEG | 3 | NEG |
| * | DL2-3501-0114 | 1.9 | NEG | 4 | NEG |
| anti-VZV | E0-2606-0011 | 4.2 | NEG | 11 | NEG |
| * | E0-2606-0037 | 1.9 | NEG | 1 | NEG |
| * | E0-2606-0142 | 0.0 | NEG | 2 | NEG |
| * | E0-2606-0218 | 57.4 | POS | 64 | POS |
| * | E1-3402-0503 | 1.7 | NEG | 11 | NEG |
| * | E1-3402-0518 | 1.0 | NEG | 2 | NEG |
| * | E1-3402-0548 | 1.4 | NEG | 2 | NEG |
| * | E1-3402-0567 | 0.4 | NEG | 2 | NEG |
| * | DL3-3512-0054 | 0.8 | NEG | 2 | NEG |
| * | DL3-3512-0065 | 0.7 | NEG | 2 | NEG |
{19}
| RF Positive | DL4-3501-0082 | 0.0 | NEG | 1 | NEG |
| --- | --- | --- | --- | --- | --- |
| “ | DL4-3501-0085 | 1.1 | NEG | 5 | NEG |
| “ | DL4-3501-0095 | 159.6 | POS | 221 | POS |
| “ | DL4-3501-0105 | 4.9 | NEG | 19.4 | POS |
| “ | DL4-3501-0108 | 0.0 | NEG | 2 | NEG |
| “ | DL4-3501-0115 | 1 | NEG | 6 | NEG |
| “ | DL4-3501-0120 | 1.2 | NEG | 3 | NEG |
| “ | DL4-3501-0125 | 0.5 | NEG | 5 | NEG |
| “ | DL4-3501-0148 | 0.6 | NEG | 2 | NEG |
| “ | DL4-3501-0154 | 0.8 | NEG | 2 | NEG |
| anti-HSV 1 or 2 | AB3-2402-0001 | 27.7 | POS | 31 | POS |
| “ | AB3-2402-0002 | 3.4 | NEG | 2 | NEG |
| “ | AB3-2402-0003 | 2 | NEG | 1 | NEG |
| “ | AB3-2402-0004 | 0.7 | NEG | 1 | NEG |
| “ | AB3-2402-0007 | 1.7 | NEG | 2 | NEG |
| “ | AB3-2402-0008 | 0.0 | NEG | 1 | NEG |
| “ | AB3-2402-0009 | 0.0 | NEG | 1 | NEG |
| “ | AB3-2402-0010 | 0.0 | NEG | 1 | NEG |
| “ | AB3-2402-0011 | 0.6 | NEG | 2 | NEG |
| “ | AB3-2402-0012 | 0.9 | NEG | 0 | NEG |
| Measles IgG | EB4-1205-0004 | 0.1 | NEG | 2 | NEG |
| “ | EB4-2707-0006 | 29.7 | POS | 59 | POS |
| “ | EB4-2707-0010 | 150.8 | POS | 222 | POS |
| “ | EB4-2707-0014 | 0.9 | NEG | 2 | NEG |
| “ | EB4-2707-0015 | 0.0 | NEG | 3 | NEG |
| “ | EB4-2707-0016 | 0.0 | NEG | 10 | NEG |
| “ | EB4-2707-0020 | 14.1 | POS | 32 | POS |
| “ | EB4-2707-0022 | 4.5 | NEG | 1 | NEG |
| “ | EB4-2707-0023 | 0.0 | NEG | 8.9 | NEG |
| “ | EB4-2707-0030 | 147.0 | POS | 211 | POS |
Quality control data for the Diagnostics Pasteur and Immuno 1 Toxoplasma IgG determinations are presented in Table 10 for the results in Table 9 and show compliance with specifications.
Table 10. Quality Control Data for Diagnostic Pasteur and Immuno 1 Toxoplasma Testing of Interference Samples
| METHOD/CONTROL | OBTAINED | SPECIFICATION | RESULT |
| --- | --- | --- | --- |
| Platelia
Pos Contr 1/Neg Contr
Pos Contr 3 | 3.4
0.972 OD | >2
>0.8 OD | Valid
Valid |
| Immuno 1
· Medical Pool 1
· Medical Pool 2
· Medical Pool 4 | 0.3 IU/mL
15.3 IU/mL
106.8 IU/mL | <4 IU/mL
9.8 to 18.2 IU/mL
65 to 121 IU/mL | Valid
Valid
Valid |
