(492 days)
The assay is to be used to detect antibodies in a single serum specimen. The results of the assay are to be used as an aid in the diagnosis of Systemic Lupus Erythematosus (SLE). FOR IN VITRO DIAGNOSTIC USE.
The Ribosomal P ELISA test is an enzyme-linked immunosorbent assay (ELISA) for the detection and semi-quantitation of IgG antibodies to Ribosomal P in human sera. The Ribosomal P ELISA test is an enzyme linked immunosorbent assay to detect IgG, M, A, antibodies to Ribosomal P. Purified Ribosomal P antigen is attached to a solid phase microtiter well. Diluted test sera is added to each well. If the antibodies are present that recognize the antigen, they will bind to the antigen in the well. After incubation the wells are washed to remove unbound antibody. An enzyme labeled antihuman IgG, M. A is added to each well. If antibody is present it will bind to the antibody attached to the antigen on well. After incubation the wells are washed to remove unbound conjugate. A substrate solution is added to each well. If enzyme is present the substrate will undergo a color change. After an incubation period the reaction is stopped and the color intensity is measured photometrically, producing an indirect measurement of specific antibody in the patient specimen.
Here's an analysis of the provided information regarding the acceptance criteria and study for the Ribosomal P ELISA Test Kit:
Acceptance Criteria and Reported Device Performance
| Acceptance Criteria Category | Acceptance Criteria (Implicit/Explicit) | Reported Device Performance |
|---|---|---|
| Sensitivity | Acceptable relative sensitivity to Ouchterlony method. While no specific numeric target is given, the high value suggests an expectation of strong agreement. | Relative Sensitivity = 100% (95% CI: 93.5%-100%) (46/46 samples positive by Ouchterlony were positive by the device). |
| Specificity | Acceptable relative specificity to Ouchterlony method. While no specific numeric target is given, the high value suggests an expectation of strong agreement. | Relative Specificity = 99.3% (95% CI: 97.8%-100%) (136/137 samples negative by Ouchterlony were negative by the device). |
| Agreement | Acceptable overall agreement with the Ouchterlony method. | Relative Agreement = 99.5% (95% CI: 98.4%-100%) (182/183 samples showed agreement). |
| Precision (C.V.) | Coefficient of Variation (C.V.) should be less than 15% with proper technique. | Intra-Assay and Inter-Assay C.V.s: Most reported C.V.s for Sera 1-4 are well below 15%. Serum 5 has an inter-assay C.V. of 25.6% and some individual assay C.V.'s of 19.6%. Serum 6 has even higher C.V.s (46.3%-48.0%). This suggests the device meets the criteria for some serum concentrations but not others, particularly at low values. |
| Linearity | The assay should be semi-quantitative, meaning there should be a strong correlation between index values and log2 of dilution. | Linearity (r-value): 0.991 to 0.997 for five positive sera when comparing the Ribosomal P Index Value to log2 of dilution. This indicates excellent linearity and confirms its semi-quantitative nature. |
| Cross-Reactivity | Antibodies to alternate autoimmune antigens (Ro, La, Scl-70, Jo-1, Sm, RNP, DNA) should not cross-react with the Ribosomal P ELISA kit. | Zero cross-reactivity observed: All 19 sera tested with high levels of antibodies to other autoimmune antigens produced negative interpretations (Immunoprobe Index Value < 0.40, the interpretation threshold for "negative" implied by the sensitivity/specificity table where 0 is assigned to negative and 1 to positive, and based on values reported). |
Study Details
-
Sample sizes used for the test set and the data provenance:
- Test Set (Sensitivity/Specificity): 183 sera (46 clinically defined lupus patients, 137 normal individuals).
- Data Provenance: Not explicitly stated, but the mention of a "lupus cohort" suggests these were clinical samples. It's likely retrospective as the Ouchterlony analysis would have been performed previously or as part of a comparative retrospective study. The "lupus cohort" (451 sera) mentioned in the summary, while a larger group, isn't the specific test set used for sensitivity/specificity calculations.
-
Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- Number of Experts: Not specified.
- Qualifications: "Clinically defined lupus" implies a consensus diagnosis by clinicians, likely based on ACR criteria, but the specific expert roles (e.g., rheumatologists) and their experience are not detailed. The Ouchterlony analysis itself would have been performed and interpreted by laboratory technicians/scientists.
-
Adjudication method for the test set:
- Not applicable in the traditional sense for diagnostic assays. The "ground truth" was established by the "clinically defined lupus" status and the results of the Ouchterlony analysis, which is considered the reference method in this comparison.
-
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, this is an in vitro diagnostic (IVD) ELISA kit, not an AI-based image analysis or clinical decision support system. Therefore, MRMC studies are not applicable.
-
If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:
- Yes, the performance presented for sensitivity, specificity, precision, linearity, and cross-reactivity is standalone performance of the ELISA kit. There is no human intervention in the interpretation of the photometric readings beyond following the kit's instructions for cut-off determination.
-
The type of ground truth used (expert consensus, pathology, outcomes data, etc.):
- For sensitivity and specificity: Ouchterlony analysis results alongside "clinically defined lupus" status. Ouchterlony is a laboratory-based serological test, considered a reference method for antibody detection.
- For cross-reactivity: The specificity of other known autoantibodies was the ground truth.
-
The sample size for the training set:
- Not applicable in the context of an ELISA kit. ELISA kits do not "train" on data in the same way machine learning models do. The assay is designed chemically and biologically. The "clinical studies" mentioned (451 sera from a lupus cohort) likely served to characterize the kit's performance in a broader population, not as a training set in an AI sense.
-
How the ground truth for the training set was established:
- Not applicable, as there is no "training set" in the AI sense for this type of device. The design and validation of the kit rely on established immunological principles and laboratory testing methods.
{0}------------------------------------------------
K950169
Summary of Safety and Effectiveness Information Ribosomal P ELISA Test Kit
MAY 2 3 1996
- I. Immuno Probe Inc. 1306 Bailes Lane, Suite F Frederick, Maryland Contact person: William Boteler Telephone: 301-695-7920 Date of preparation: December 22, 1995
- ll. Description of Device
The Ribosomal P ELISA test is an enzyme-linked immunosorbent assay (ELISA) for the detection and semi-quantitation of IgG antibodies to Ribosomal P in human sera. The assay is to be used to detect antibodies in a single serum specimen. The results of the assay are to be used as an aid in the diagnosis of Systemic Lupus Erythematosus (SLE). FOR IN VITRO DIAGNOSTIC USE.
The Ribosomal P ELISA test is an enzyme linked immunosorbent assay to detect IgG, M, A, antibodies to Ribosomal P. Purified Ribosomal P antigen is attached to a solid phase microtiter well. Diluted test sera is added to each well. If the antibodies are present that recognize the antigen, they will bind to the antigen in the well. After incubation the wells are washed to remove unbound antibody. An enzyme labeled antihuman IgG, M. A is added to each well. If antibody is present it will bind to the antibody attached to the antigen on well. After incubation the wells are washed to remove unbound conjugate. A substrate solution is added to each well. If enzyme is present the substrate will undergo a color change. After an incubation period the reaction is stopped and the color intensity is measured photometrically, producing an indirect measurement of specific antibody in the patient specimen.
- III. Clinical Data
Clinical studies were conducted using 451 sera from a lupus cohort. Forty five were found to be positive for a prevalence rate of 9.98%. The data indicate that the prevalence of Ribosomal P antibody found in this cohort using the Ribosomal P device is similar to that found in the literature (12-20%).
{1}------------------------------------------------
XI. Performance Characteristics
- Relative sensitivity and specificity. The Ribosomal P ELISA test results were compared to results obtained by ouchterlony analysis of serum from clinically defined lupus (n=46) and normals (n=137). The results of the study are summarized in Table 1.
Table 1 Sensitivity and Specificity of the Ribosomal P Test Kit Relative toOuchterlony
Immuno Probe, Inc.
| Positive | Equivocal | Negative | Total | ||
|---|---|---|---|---|---|
| Ouchterlony | Positive | 46 | 0 | 0 | 46 |
| Negative | 1 | 0 | 136 | 137 | |
| Total | 47 | 0 | 136 | 183 |
| Relative Sensitivity = 46/46 = 100% | 95% Confidence Interval = 93.5%-100% |
|---|---|
| Relative Specificity = 136/137 = 99.3% | 95% Confidence Interval = 97.8%-100% |
| Relative Agreement = 182/183 = 99.5% | 95% Confidence Interval = 98.4%-100% |
The 95% confidence interval for relative sensitivity was calculated assuming one false negative.
{2}------------------------------------------------
2. Precision
The precision of the Ribosomal P kit was determined by testing seven different sera eight times each on three different assays The data is summarized in Table 2. With proper technique the user should obtain C. V.'s of less than 15%.
Table 2 Ribosomal P Precision Data
| Assay 1 (n=8) | Assay 2 (n=8) | Assay 3 (n=8) | Inter Assay (n=24) | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Serum # | X | S.D. | C.V. | X | S.D. | C.V. | X | S.D. | C.V. | X | S.D | C.V. |
| 1 | 1.57 | 0.117 | 7.4% | 1.62 | 0.113 | 7.0% | 1.50 | 0.134 | 8.9% | 1.57 | 0.127 | 8.1% |
| 2 | 1.68 | 0.176 | 10.5% | 1.60 | 0.095 | 5.9% | 1.66 | 0.148 | 8.9% | 1.65 | 0.143 | 8.7% |
| 3 | 2.98 | 0.113 | 3.8% | 2.83 | 0.128 | 4.5% | 2.74 | 0.127 | 4.6% | 2.85 | 0.155 | 5.5% |
| 4 | 2.89 | 0.115 | 4.09% | 2.95 | 0.135 | 4.6% | 2.94 | 0.068 | 2.3% | 2.92 | 0.109 | 3.7% |
| 5 | 0.29 | 0.027 | 9.29% | 0.18 | 0.035 | 19.6% | 0.20 | 0.039 | 19.6% | 0.22 | 0.056 | 25.6% |
| 6 | 0.09 | 0.042 | 46.3% | 0.08 | 0.016 | 20.5% | 0.08 | 0.037 | 46.5% | 0.10 | 0.048 | 48.0% |
- = Mean Ribosomal P Value X
S.D. = Standard Deviation
C.V. = Coefficient of Variation
3. Linearity
The Ribosomal P index values were determined for serial twofold dilutions of five positive sera. The index values were compared to log2 of dilution by standard linear regression. The data in table # 3 indicates that the assay is semi-quantitative.
Table 3 Linearity
| IndexSerum # | Neat | 1:2 | 1:4 | 1:8 | 1:16 | 1:32 | 1:64 | 1:128 | r |
|---|---|---|---|---|---|---|---|---|---|
| 1 | 2.70 | 2.52 | 2.24 | 1.93 | 1.57 | 1.33 | 0.98 | 0.997 | |
| 2 | 2.53 | 2.29 | 1.99 | 1.57 | 1.20 | 0.86 | 0.997 | ||
| 3 | 2.89 | 2.71 | 2.47 | 2.23 | 1.93 | 1.57 | 1.20 | 0.90 | 0.994 |
| 4 | 3.68 | 3.18 | 2.59 | 1.94 | 1.59 | 1.00 | 0.68 | 0.997 | |
| 5 | 2.09 | 1.38 | 0.94 | 0.991 |
Linear regression compared Ribosomal P Index Value to log, of dilution
{3}------------------------------------------------
4. Cross Reactivity Data
Sera containing high levels of antibodies to potentially cross reactive antigens were assayed on the Ribosomal P ELISA kit. The data in Table 4 indicates that antibodies to alternate autoimmune antigens do not cross react with the Ribosomal P ELISA kit.
| Serum # | Immunoprobe Index | Interpretation | Specificity |
|---|---|---|---|
| Value | |||
| 1 | 0.21 | - | Ro |
| 2 | 0.18 | - | Ro |
| 3 | 0.17 | - | Ro |
| 4 | 0.13 | - | La |
| 5 | 0.09 | - | La |
| 6 | 0.10 | - | La |
| 7 | 0.09 | - | Scl-70 |
| 8 | 0.18 | - | Scl-70 |
| 9 | 0.17 | - | Scl-70 |
| 10 | 0.15 | - | Jo-1 |
| 11 | 0.18 | - | Jo-1 |
| 12 | 0.15 | - | Jo-1 |
| 13 | 0.38 | - | Sm |
| 14 | 0.43 | - | Sm |
| 15 | 0.40 | - | Sm |
| 16 | 0.19 | - | RNP |
| 17 | 0.15 | - | RNP |
| 18 | 0.14 | - | RNP |
| 19 | 0.14 | - | DNA |
Table 4 Cross Reactivity
- Prevalence. Clinical studies were conducted using 451 sera from a lupus cohort. Forty five were found to be positive for a prevalence rate of 9.98%. The data indicate that the prevalence of Ribosomal P antibody found in this cohort using the Ribosomal P device is similar to that found in the literature (12-20%)
§ 866.5100 Antinuclear antibody immunological test system.
(a)
Identification. An antinuclear antibody immunological test system is a device that consists of the reagents used to measure by immunochemical techniques the autoimmune antibodies in serum, other body fluids, and tissues that react with cellular nuclear constituents (molecules present in the nucleus of a cell, such as ribonucleic acid, deoxyribonucleic acid, or nuclear proteins). The measurements aid in the diagnosis of systemic lupus erythematosus (a multisystem autoimmune disease in which antibodies attack the victim's own tissues), hepatitis (a liver disease), rheumatoid arthritis, Sjögren's syndrome (arthritis with inflammation of the eye, eyelid, and salivary glands), and systemic sclerosis (chronic hardening and shrinking of many body tissues).(b)
Classification. Class II (performance standards).