(226 days)
This in vitro diagnostic method in intended to quantitatively and qualitatively measure Toxoplasma IgG in human serum on the Technicon Immuno 10 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.
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Here's an analysis of the acceptance criteria and study details for the TECHNICON TOXOPLASMA IgG METHOD FOR THE IMMUNO 1® SYSTEM, based on the provided document:
Acceptance Criteria and Device Performance
The core performance of the device is assessed against a similar device previously cleared by the FDA: the Abbott IMx Toxoplasma IgG assay. The acceptance criteria are implicit in the comparative study, aiming to demonstrate substantial equivalence in terms of sensitivity, specificity, and overall agreement.
Table 1: Acceptance Criteria and Reported Device Performance
| Performance Metric | Acceptance Criteria (Implicit) | Reported Device Performance (IFA Resolved, Combined Clinical Sites & Lots) |
|---|---|---|
| Sensitivity | Comparable to Abbott IMx | Lot 1: 96.8% (95% CI: 93.2 - 98.8%)Lot 2: 95.2% (95% CI: 91.1 - 97.8%) |
| Specificity | Comparable to Abbott IMx | Lot 1: 96.7% (95% CI: 94.5 - 98.2%)Lot 2: 96.5% (95% CI: 94.2 - 98.1%) |
| Overall Agreement | Comparable to Abbott IMx | Lot 1: 96.8% (95% CI: 95.0 - 98.0%)Lot 2: 96.1% (95% CI: 94.2 - 97.5%) |
| Linearity | Demonstrated over 12-300 IU/mL | R-values generally >= 0.99 for individual patients (Table 7) |
| Interference | No clinically significant effect | Hemolyzed (up to 1000 mg/dL), lipemic (up to 900 mg/dL), icteric (up to 25 mg/dL), and various common antibodies showed no significant interference. |
| Correlation with WHO Standard (TOXS-60) | High correlation (Figure 1) | Y = 0.905 X + 1.618, R² = 0.9998 |
Study Proving Device Meets Acceptance Criteria:
The study conducted to prove the device meets acceptance criteria is a method comparison study against the Abbott IMx Toxoplasma IgG assay, combined with linearity and interference studies.
The comparative data was collected at two outside clinical trial sites:
- University of Texas Medical Branch, Laboratory Medical Clinical Chemistry, Galveston, Texas
- San Francisco General Hospital Clinical Laboratories, San Francisco, California
Two lots of Immuno 1® Toxoplasma IgG reagents were evaluated at each clinical site.
Detailed Study Information:
-
Table of Acceptance Criteria and Reported Device Performance: (See table above)
-
Sample Size Used for the Test Set and Data Provenance:
- Test Set Sample Size: For the comparative study with Abbott IMx, the combined test set size across both clinical sites and reagent lots (after IFA resolution) was 585 specimens (188 positive, 397 negative for both Lot 1 and Lot 2).
- Data Provenance: The data was collected from two prospective clinical trial sites in the United States: University of Texas Medical Branch, Galveston, Texas and San Francisco General Hospital, San Francisco, California.
- Initial specimens included 223 prenatal specimens from Clinical Site 1 and 225 random hospital specimens from Clinical Site 2.
- These were augmented by an additional 75 supplemental masked serum specimens at each site to increase the number of positives.
- Some specimens were frozen prior to analysis (110/298 at Site 1, 117/300 at Site 2), while unfrozen specimens were fresh or stored at 2-8°C for less than 1 week.
-
Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications:
- The primary "ground truth" for the comparative study was the Abbott IMx Toxoplasma IgG assay.
- For discrepant samples, an Indirect Fluorescent Antibody (IFA) analysis was performed to resolve results.
- The document does not specify the number of experts who performed the IFA testing or their specific qualifications (e.g., "Radiologist with 10 years of experience"). It only states that 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.
-
Adjudication Method for the Test Set:
- For the main comparative study with Abbott IMx, discrepant samples at clinical site 2 were subsequently tested twice on both instruments (IMMUNO 1 and IMx) and classified as either positive or negative based on "two out of three results". This implies a form of consensus, where if the two re-tests agreed, that settled the classification.
- Furthermore, IFA analysis was used for resolution if there was a discrepancy between the IMMUNO 1 and IMx results. "Resolution by IFA excludes a discrepant result if agreement between IFA and Immuno 1 is found." This suggests a hierarchical adjudication: first IMx comparison, then re-testing, then IFA as a tie-breaker or gold standard for specific discrepancies.
-
If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was done:
- No, an MRMC comparative effectiveness study was not done. This study evaluates the performance of a diagnostic assay (an in-vitro diagnostic device), not a device involving human interpretation (like imaging or AI algorithms). Therefore, the concept of "human readers improve with AI vs without AI assistance" is not applicable here.
-
If a Standalone (i.e., algorithm only without human-in-the-loop performance) was done:
- Yes, this is a standalone device performance study. The Technicon IMMUNO 1® Toxoplasma IgG method is an automated in vitro diagnostic assay. Its performance (quantitatively measuring Toxoplasma IgG) is assessed directly through laboratory testing, without human interpretation of images or other subjective inputs that would require a human-in-the-loop component. The results are quantitative IU/mL values.
-
The Type of Ground Truth Used:
- The primary ground truth for the comparative study was the Abbott IMx Toxoplasma IgG assay, which is itself an FDA-cleared device for the same indication.
- For resolving discrepancies, Indirect Fluorescent Antibody (IFA) analysis was used. IFA is a laboratory technique often considered a reference method for antibody detection, especially in toxoplasmosis serology.
- Additionally, the device's calibration is traceable to the WHO anti-Toxoplasma Serum International Standard (TOXS-60), which serves as a recognized reference standard for quantifying Toxoplasma IgG.
-
The Sample Size for the Training Set:
- This document describes a clinical validation study for a new assay, not an AI or machine learning algorithm. Therefore, the concept of a "training set" in the context of machine learning is not applicable. The device is an instrument and reagent system that measures IgG levels based on established biochemical principles, not learned patterns from data.
-
How the Ground Truth for the Training Set was Established:
- As noted above, a "training set" is not relevant for this type of IVD device. The assay's "calibration" is established using a set of six calibrators (0, 10, 20, 50, 100, 300 IU/mL) that are traceable to the WHO anti-Toxoplasma Serum International Standard (TOXS-60). This standard itself is the "ground truth" for quantitative accuracy.
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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 10 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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Image /page/1/Figure/0 description: The image is a graph that plots "WHO 2nd International Standard (IU/mL)" on the y-axis and "SETpoint Toxoplasma IgG Cals (IU/mL)" on the x-axis. The x-axis and y-axis range from 0 to 300. A linear trendline is plotted on the graph, and the equation of the line is "Y = 0.905 X + 1.618" with an R-value of 0.9998.
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:
$$\begin{array}{rcl} \mathsf{Y} = \mathsf{0.905} ,\mathsf{X} + \mathsf{1.618} \ \mathsf{R}^2 = \mathsf{0.9998} \ \mathsf{95%} ,\mathsf{CL} ,\mathsf{intercept} = \pm ,\mathsf{2.44} \ \mathsf{95%} ,\mathsf{CL} ,\mathsf{slope} = \pm ,\mathsf{0.019} \end{array}$$
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).
| TECHNICON IMMUNO 1TOXOPLASMA IgG(IU/mL) | PRENATAL SPECIMENSCLINICAL SITE 1 | HOSPITAL SPECIMENSCLINICAL SITE 2 | ||
|---|---|---|---|---|
| NO. OFSPECIMENS | % OFTOTAL | NO. OFSPECIMENS | % OFTOTAL | |
| < 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 |
TABLE 1: DISTRIBUTION OF SERUM TECHNICON IMMUNO 1 TOXOPLASMA IgG VALUES IN PRENATAL AND HOSPITAL SPECIMENS
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℃ 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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Site 1 University of Texas Medical Branch
| Immuno 1 Rgts &Sample Description | Number ofResults byIMxClassification | No. ofImmuno 1Results InAgreementwith IMxClassification | Sensitivity,Specificity orOverallAgreement(%) | 95% ConfidenceLimits(%) |
|---|---|---|---|---|
| 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 ofResults byIMxClassification | No. ofImmuno 1Results inAgreementwith IMxClassification | Sensitivity,Specificity orOverallAgreement(%) | 95% ConfidenceLimits(%) | ||||
|---|---|---|---|---|---|---|---|---|---|
| Immuno 1 Rgts &Sample Description | Number ofResolvedResults | No. ofImmuno 1Results inAgreementwith ResolvedResults | Sensitivity,Specificity orOverallAgreement(%) | 95% ConfidenceLimits(%) | Immuno 1 Lot 1 Rgts | ||||
| Immuno 1 Lot 1 Rgts | Site 2 SuppliedSensitivitySpecificityOverall Agreement | 43182225 | 35170205 | 81.493.491.1 | 66.6 - 91.688.8 - 96.586.6 - 94.5 | ||||
| Site 1 SuppliedSensitivitySpecificityOverall Agreement | 49172221 | 45170215 | 91.898.897.3 | 80.4 - 97.795.9 - 99.994.2 - 99.0 | Supplemental SamplesSensitivitySpecificityOverall Agreement | 482775 | 482674 | 10096.398.7 | 92.6 - 10081.0 - 99.992.8 - 100 |
| Supplemental SamplesSensitivitySpecificityOverall Agreement | 541973 | 541872 | 10094.798.6 | 93.4 - 10074.0 - 99.992.6 - 100 | CombinedSensitivitySpecificityOverall Agreement | 91209300 | 83196279 | 91.293.893.0 | 83.4 - 96.189.6 - 96.689.5 - 95.6 |
| CombinedSensitivitySpecificityOverall Agreement | 103191294 | 99188287 | 96.198.497.6 | 90.4 - 98.995.5 - 99.795.2 - 99.0 | Immuno 1 Lot 2 Rgts | ||||
| Immuno 1 Lot 2 Rgts | Site 2 SuppliedSensitivitySpecificityOverall Agreement | 44181225 | 33170203 | 75.093.990.2 | 59.7 - 86.889.4 - 96.985.6 - 93.8 | ||||
| Site 1 SuppliedSensitivitySpecificityOverall Agreement | 49172221 | 46169215 | 93.998.397.3 | 83.1 - 98.795.0 - 99.694.2 - 99.0 | Supplemental SamplesSensitivitySpecificityOverall Agreement | 482775 | 472673 | 97.996.397.3 | 88.9 - 99.981.0 - 99.990.7 - 99.7 |
| Supplemental SamplesSensitivitySpecificityOverall Agreement | 541973 | 531871 | 98.294.797.3 | 90.1 - 10074.0 - 99.990.5 - 99.7 | CombinedSensitivitySpecificityOverall Agreement | 92208300 | 80196276 | 87.094.292.0 | 78.3 - 93.190.1 - 97.088.3 - 94.8 |
| CombinedSensitivitySpecificityOverall Agreement | 103191294 | 99187286 | 96.197.997.3 | 90.4 - 98.994.7 - 99.494.7 - 98.8 |
s Medical Branch - IFA Resolved
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Site 2 San Francisco General Hospital
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| Immuno 1 Rgts &Sample Description | Number ofResolvedResults | No. ofImmuno 1Results inAgreementwith ResolvedResults | Sensitivity,Specificity orOverallAgreement(%) | 95% ConfidenceLimits(%) |
|---|---|---|---|---|
| Immuno 1 Lot 1 Rgts | ||||
| Site 2 SuppliedSensitivitySpecificityOverall Agreement | 43182225 | 35170205 | 81.493.491.1 | 66.6 - 91.688.8 - 96.586.6 - 94.5 |
| Supplemental SamplesSensitivitySpecificityOverall Agreement | 482775 | 482674 | 10096.398.7 | 92.6 - 10081.0 - 99.992.8 - 100 |
| CombinedSensitivitySpecificityOverall Agreement | 85206291 | 83196279 | 97.695.195.9 | 91.8 - 99.791.3 - 97.692.9 - 97.9 |
| Immuno 1 Lot 2 Rgts | ||||
| Site 2 SuppliedSensitivitySpecificityOverall Agreement | 44181225 | 33170203 | 75.093.990.2 | 59.7 - 86.889.4 - 96.985.6 - 93.8 |
| Supplemental SamplesSensitivitySpecificityOverall Agreement | 482775 | 472674 | 97.996.398.7 | 88.9 - 99.981.0 - 99.992.8 - 100 |
| CombinedSensitivitySpecificityOverall Agreement | 85206291 | 80196276 | 94.195.194.8 | 86.8 - 98.191.3 - 97.691.6 - 97.1 |
Site 2 San Francisco General Hospital - IFA Resolved
:
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| Immuno 1 Rgts &Sample Description | Number ofResults byIMxClassification | No. ofImmuno 1Results inAgreementwith IMxClassification | Sensitivity,Specificity orOverallAgreement(%) | 95% ConfidenceLimits(%) |
|---|---|---|---|---|
| Immuno 1 Lot 1 RgtsAll 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 RgtsAll 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: Unresolved Results
Combined Clinical Site 1 & 2 Results: IFA Resolved
| Immuno 1 Rgts &Sample Description | Number ofResolvedResults | No. ofImmuno 1Results inAgreementwith ResolvedResults | Sensitivity,Specificity orOverallAgreement(%) | 95% ConfidenceLimits(%) |
|---|---|---|---|---|
| Immuno 1 Lot 1 RgtsAll 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 RgtsAll 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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| STUDYLOCATION | COMPARATIVEMETHOD | IMMUNO 1DISCREPANCIES | DISCREPANTRESULTS | IFAPOSITIVE | IFANEGATIVE |
|---|---|---|---|---|---|
| Clinical Site 1Lot 1 Rgts | Abbott IMx | False NegativeFalse Positive | 56 | 43 | 13 |
| Lot 2 Rgts | Abbott IMx | False NegativeFalse Positive | 57 | 43 | 14 |
| Clinical Site 2Lot 1 Rgts | Abbott IMx | False NegativeFalse Positive | 813 | 23 | 610 |
| Lot 2 Rgts | Abbott IMx | False NegativeFalse Positive | 1212 | 52 | 710 |
Table 3: IFA RESULTS ON DISCREPANT SAMPLES
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.
Image /page/10/Figure/1 description: The image is a graph that plots the true positive fraction (sensitivity) on the y-axis and the false positive fraction (1 - specificity) on the x-axis. The graph shows a curve that rises sharply and then plateaus near the top. The area under the curve (AUC) is labeled as 0.990, and there is an arrow pointing to a point on the curve labeled "12 IU/mL".
(a) ROC Plot. Immuno 1 vs IMx. University of Texas Medical Branch employing TXG Lot 1 Immuno 1 Toxoplasma IgG Reagents. (Area = 0.990)
Image /page/10/Figure/3 description: This image is a graph that plots the true positive fraction (sensitivity) against the false positive fraction (1-specificity). The graph shows a curve that rises sharply and then plateaus near the top. The area under the curve is labeled as 0.989. There is also a label that says 12 IU/mL.
(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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Image /page/11/Figure/0 description: The image is a ROC plot titled "IMMUNO1 ve IMx TOXOPLASMA IgG Rgt Lot 1 SAN FRANCISCO GEN HOSPITAL". The x-axis is labeled "FALSE POS FRACTION (1 - specificity)" and ranges from 0.0 to 1.0. The y-axis is labeled "TRUE POS FRACTION (sensitivity)" and ranges from 0.0 to 1.0. The area under the curve is 0.967, and there is an arrow pointing to a point on the curve labeled "12 IU/mL".
(c). ROC Plot. Immuno 1 vs IMx. San Francisco General Hospital employing Lot 1 Immuno 1 Toxoplasma IgG Reagents. (Area = 0.967)
Image /page/11/Figure/2 description: The image is a ROC plot comparing IMMUNO1 vs IMx TOXOPLASMA IgG. The plot shows the true positive fraction (sensitivity) on the y-axis and the false positive fraction (1 - specificity) on the x-axis. The area under the curve (AUC) is 0.968, and there is an arrow pointing to a point on the curve labeled "12 IU/mL".
(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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ROC Plot Areas for Immuno1 relative to the IMx Table 4. Toxoplasma IgG Method
| CLINICAL SITE | Immuno 1Reagent Lot | ComparativeMethod | ROC Area |
|---|---|---|---|
| Univ of Texas MB | Lot 1 | IMx | 0.990 |
| Univ of Texas MB | Lot 2 | IMx | 0.989 |
| San Francisco GH | Lot 1 | IMx | 0.967 |
| San Francisco GH | Lot 2 | IMx | 0.968 |
| Combined Clinical Sites | Lot 1 | IMx | 0.980 |
| Combined Clinical Sites | 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 MBLOT 1 REAGENTS | Pos Neg Pos 104 1 Neg 2 191 | 99.0 | |||||||||
| San Francisco GHLOT 1 REAGENTS | Pos Neg Pos 91 4 Neg 0 205 | 98.7 |
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 1Rubella IgGReagent 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.
Image /page/13/Figure/3 description: This image is a scatter plot comparing Reagent Lot 1 (TXG) and Reagent Lot 2 (TYG), both measured in IU/mL. The x-axis represents Reagent Lot 1, and the y-axis represents Reagent Lot 2, with values ranging from 0 to 300 IU/mL on both axes. The plot shows a positive correlation between the two reagent lots, with data points clustered around a diagonal line. This suggests a strong agreement between the measurements obtained using the two different reagent lots.
(8) 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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Image /page/14/Figure/0 description: The image is a scatter plot comparing Reagent Lot 1 (TXQ) IU/mL on the x-axis and Reagent Lot 2 (TYQ) IU/mL on the y-axis. The plot shows a positive correlation between the two reagent lots, with data points scattered around a straight line. The x and y axes range from 0 to 300, and the data points are clustered along the diagonal, indicating a strong agreement between the two reagent lots. The plot suggests that the two reagent lots are comparable in terms of their activity or concentration.
Toxoplasma IgG reagent Lot 1 versus Lot 2. Data was collected at the San
Francisco General Hospital. (b)
..:
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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.
Image /page/15/Figure/2 description: This figure is a scatter plot showing the relationship between IMMUNO 1 Toxoplasma IgG IU/mL and IFA (1 = <1:16 TITRE). The x-axis represents IFA values ranging from 0 to 512, while the y-axis represents IMMUNO 1 Toxoplasma IgG IU/mL values ranging from 0 to 350. There are several data points scattered across the plot, with clusters around IFA values of 64 and 256, and a few points at 512. The data points show a general trend of increasing IMMUNO 1 Toxoplasma IgG IU/mL with increasing IFA values.
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 IU/mL with one result having an Immuno 1 value of 5 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.
| Sample | DilFactor | Run 1Rep 1 | Run 1Rep 2 | Run 2Rep 1 | Run 2Rep 2 | TotalCV | 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 |
Table 7. Linearity study.
{17}------------------------------------------------
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 bilrubin) samples have no clinically significant effect on method performance, Table 8. Patient samples containing theumatoid 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 | ||
|---|---|---|
TRIGLYCERIDE
| mg/dL | IU/mLTOXO 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 |
| mg/dL | IU/mLTOXO 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/mLTOXO 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 | |
| mg/dL | IU/mLTOXO 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 |
BILIRUBIN
{18}------------------------------------------------
Potential Immunlogical 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.
| Antibody | Sample ID | PlateliaToxoplasma IgGIU/mL | Immuno1Toxoplasma IgGIU/mL | ||
|---|---|---|---|---|---|
| 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 |
Table 9 Interference study results.
{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 |
|---|---|---|---|
| PlateliaPos Contrl 1/Neg Contrl | 3.4 | > 2 | Valid |
| Pos Contrl 3 | 0.972 OD | > 0.8 OD | Valid |
| Immuno 1 | |||
| • Medical Pool 1 | 0.3 IU/mL | < 4 IU/mL | Valid |
| Medical Pool 2 | 15.3 IU/mL | 9.8 to 18.2 IU/mL | Valid |
| Medical Pool 4 | 106.8 IU/mL | 65 to 121 IU/mL | Valid |
§ 866.3780
Toxoplasma gondii serological reagents.(a)
Identification. Toxoplasma gondii serological reagents are devices that consist of antigens and antisera used in serological tests to identify antibodies toToxoplasma gondii in serum. Additionally, some of these reagents consist of antisera conjugated with a fluorescent dye (immunofluorescent reagents) used to identifyToxoplasma gondii from clinical specimens. The identification aids in the diagnosis of toxoplasmosis caused by the parasitic protozoanToxoplasma 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.(b)
Classification. Class II (performance standards).