IS-ANTI-SM TEST SYSTEM

{0} K970220 APR - 8 1997 # 510(k) Summary of Safety and Effectiveness This summary of safety and effectiveness information is being submitted in accordance with the requirements of SMDA 1990 and 21 CFR 807.92. The assigned 510(k) number is: ________________ ## Applicant Information: Date Prepared: January 15, 1997 Name: Diamedix Corporation Address: 2140 N. Miami Avenue Miami, FL 33127 Contact Person: Dr. Lynne Stirling Phone Number: 305-324-2354 Fax Number: 305-324-2585 ## Device Information: Trade Name: Is-(immunosimplicity)-anti-Sm Test System Common Name: Anti-Sm EIA Test Classification Name: Extractable Antinuclear Antibody ## Equivalent Device: Helix Diagnostics Enzyme Immunoassay Anti-Sm Antibody Test Kit ## Device Description: The Is-anti-Sm Test Kit System is an enzyme-linked immunosorbent assay (ELISA) for the detection and semi-quantitation of IgG to Sm antigen in human serum. ## Intended use: The assay is intended for use in detecting antibodies to Sm antigen in a single human serum sample. The results of the assay are to be used as an aid in the diagnosis of autoimmune disorders. ## Comparison to Predicate Device: The Is-anti-Sm Test System is an enzyme-linked immunosorbent assay to detect IgG to Sm antigen in human serum. Purified Sm antigen is attached to a solid phase microtiter well. Diluted test sera are added to each well. If antibodies which recognize the Sm antigen are present in the patient sample, they will bind to the antigen in the well. After incubation, the wells are washed to remove unbound antibody. An enzyme-labeled anti-human immunoglobulin (conjugate) is added to each test well. If antibody is present the enzyme-linked antibody will bind to it. After incubation, the wells are washed to remove unbound conjugate. A substrate solution is then added to each well. If enzyme is present from the prior step, the substrate will be converted to produce a colored product. The reaction is stopped and the color intensity is measured photometrically providing an indirect measure of the specific antibody present in the patient sample. 000177 {1} Summary of Safety and Effectiveness ## Performance Characteristics ### A. Comparison Testing The Diamedix Is-anti-Sm Test Kit was evaluated relative to another commercially available anti-Sm ELISA test kit using 100 sera from normal blood donors and 50 sera from autoimmune patients. The results are summarized in Table 1 below. | Table 1 | Manual | | | MAGO | | | | --- | --- | --- | --- | --- | --- | --- | | | Number of Sera | % | 95% Confidence | Number of Sera | % | 95% Confidence | | Relative Sensitivity | 34/39 | 87 | 73-96 | 35/41 | 85 | 71-94 | | Relative Specificity | 107/107 | 100 | 97-100 | 107/107 | 100 | 97-100 | | Agreement | 141/146* | 97 | 92-99 | 142/148** | 96 | 92-99 | * Two equivocal and two borderline samples were excluded from the calculations. ** Two borderline samples were excluded from the calculations. Five sera negative by Is-anti-Sm (manual) and positive by the comparative method were negative when tested by a third method. Six sera negative by Is-anti-Sm (MAGO) and positive by the comparative method were negative when tested by a third method. All discordant sera were from patient samples. ### B. Linearity Figures 1 and 2 show typical examples of Is-anti-Sm Test Kit linearity. The figures depict the results of the Calibrator tested by Is-anti-Sm after serial two-fold manual dilutions in Sample Diluent. Separate dilutions were tested both manually and with MAGO. The results demonstrate a high degree of linearity for Is-anti-Sm Test Kit throughout the testing range.  Figure 1 Manual Linearity  Figure 2 MAGO Linearity 000178 {2} C. Precision Testing The precision of the Is-anti-Sm Test Kit was determined at Diamedix by testing six different sera and kit Calibrator and controls in two runs on three different days. The intra- and interassay precision is shown in Table 2 below. | SERUM | Overall MEAN EU/ml | MANUAL | | MAGO | | | --- | --- | --- | --- | --- | --- | | | | INTRA-CV% | INTER-CV% | INTRA-CV % | INTER-CV % | | 1 (NEG) | 1.6 | 8.2 | 7.1 | 19.7 | 23.5 | | 2 (NEG) | 1.6 | 9.2 | 25.0 | 10.2 | 13.3 | | 3 (POS) | 56.0 | 3.2 | 3.5 | 3.9 | 4.5 | | 4 (POS) | 38.4 | 5.5 | 5.7 | 3.4 | 7.9 | | 5 (POS) | 80.7 | 3.9 | 4.6 | 2.1 | 3.4 | | 6 (POS) | 93.9 | 2.8 | 3.6 | 2.7 | 5.3 | | CAL | 104.3 | 2.8 | 4.2 | 3.7 | 6.7 | | POS CTRL | 52.6 | 3.1 | 4.2 | 5.2 | 7.6 | | NEG CTRL | 0.8 | 12.1 | 25.0 | 47.2 | 50.0 | D. Crossreactivity Twenty-four sera positive for the six autoimmune specificities were tested in Is- anti-Sm Test Kit. The results are shown in Table 3. Table 3 Crossreactivity | Sample | Is anti-Sm | Interp | Specificity | | --- | --- | --- | --- | | 1 | 2.2 | NEG | SSA | | 2 | 2.6 | NEG | SSA | | 3 | 1.4 | NEG | SSA | | 4 | 1.3 | NEG | SSA | | 5 | 2.0 | NEG | SSB | | 6 | 2.2 | NEG | SSB | | 7 | 2.1 | NEG | SSB | | 8 | 1.5 | NEG | SSB | | 9 | 78.2 | POS | Sm | | 10 | 66.4 | POS | Sm | | 11 | 103.6 | POS | Sm | | 12 | 103.1 | POS | Sm | | 13 | 7.1 | NEG | RNP | | 14 | 3.8 | NEG | RNP | | 15 | 10.2 | NEG | RNP | | 16 | 2.1 | NEG | RNP | | 17 | 2.8 | NEG | Jo-1 | | 18 | 4.0 | NEG | Jo-1 | | 19 | 3.4 | NEG | Jo-1 | | 20 | 2.6 | NEG | Jo-1 | | 21 | 1.6 | NEG | Scl-70 | | 22 | 2.0 | NEG | Scl-70 | | 23 | 2.3 | NEG | Scl-70 | | 24 | 1.9 | NEG | Scl-70 | 000179 {3} # E. Expected Values The expected values in the normal population were determined by assaying 100 normal donor sera collected in South Florida. Figures 3 and 5 show the distribution of Sm results in the normal population performed manually and on MAGO respectively. The distribution of EU/ml values for 50 clinically characterized sera along with the 100 normal donor sera are shown in Figures 4 and 6 performed manually and on MAGO respectively.  Figure 3 Manual Normals  Figure 4 Manual Expected Values  Figure 5 MAGO Normals  Figure 6 MAGO Expected Values # F. Correlation of Manual and MAGO Results Numerical comparison of EU/ml values, between manual and MAGO results for 150 samples in the Is-anti-Sm Test Kit showed a correlation of 0.99 (Pearson). 000180