Search Results

The DiaSorin Molecular Simplexa™ Congenital CMV Direct is a real-time PCR assay intended for use on the LIAISON® MDX instrument for the in vitro qualitative detection of cytomegalovirus (CMV) from saliva swabs and urine from infants less than 21 days of age. Positive results from saliva are presumptive and should be confirmed with urine. The results of the Simplexa™ Congenital CMV Direct assay should be used in conjunction with the results of other clinical findings as an aid in the diagnosis of congenital CMV infection.

This test has not been cleared for screening of blood products for the presence of CMV or for use with samples other than urine and saliva swabs.

DiaSorin Molecular's Simplexa™ Congenital CMV Positive Control Pack is intended to be used as a control with the Simplexa Congenital CMV Direct kit for use on the LIAISON MDX instrument. This control is not intended for use with other assays or systems.

The Simplexa™ Congenital CMV Direct assay is a real-time PCR system that enables the direct amplification and detection of CMV DNA from either saliva swab or urine specimens without nucleic acid extraction. The system consists of the Simplexa™ Congenital CMV Direct Reaction Mix, the LIAISON® MDX (with LIAISON® MDX Studio Software), the Direct Amplification Disc (DAD) and associated accessories.

In the Simplexa™ Congenital CMV Direct assay, bi-functional fluorescent probe-primers are used together with corresponding reverse primers to amplify CMV DNA. A well-conserved region of the CMV UL83 gene is targeted to identify CMV DNA. An internal control is used to detect PCR failure and/or inhibition.

Here's a breakdown of the acceptance criteria and the study proving the device meets them, based on the provided text:

1. Table of Acceptance Criteria and Reported Device Performance

The document doesn't explicitly state quantitative acceptance criteria in a dedicated table format. However, the reported performance metrics imply the criteria for acceptance. For the purpose of this response, I'll infer the implicit acceptance criteria based on the demonstrated performance, generally implying "high agreement" for positive and negative cases.

2. Sample Size and Data Provenance

• Retrospective Study:

  • Saliva Swab: 173 total specimens (3 removed due to indeterminate CRM result, 170 analyzed)
  • Urine: 173 total specimens
  • Provenance: "collected during the clinical study", "stored at a central site", then distributed to three (3) laboratories. The document doesn't explicitly state the country of origin for these retrospective samples, though the testing sites were in the USA. These were pre-selected positive and negative samples based on routine laboratory results.

• Prospective Study:

  • Saliva Swab: 1,859 initially collected, 6 deemed ineligible, resulting in 1,853 analyzed specimens.
  • Urine: 1,656 initially collected, 32 deemed ineligible, resulting in 1,624 analyzed specimens.
  • Provenance: Prospectively collected (frozen and/or fresh) from ten (10) collection sites across the USA and two (2) collection sites outside the USA. Testing was performed at six (6) testing sites located in the USA.

3. Number of Experts and Qualifications

The document states that a "Composite Reference Method (CRM)" was used, which involved "two (2) validated PCR followed by bi-directional sequencing assays." One (1) central laboratory performed these comparator assays.

• The document does not specify the number of experts used to establish the ground truth or their specific qualifications (e.g., radiologist with 10 years of experience). It relies on the validation of the PCR and bi-directional sequencing assays as the basis for ground truth, implying that these are established and reliable laboratory methods.

4. Adjudication Method

The ground truth for the clinical agreement studies (both retrospective and prospective) was established via a "Composite Reference Method (CRM)".
This CRM "utilized two (2) validated PCR followed by bi-directional sequencing assays. A sample had a final sequencing result of 'Detected' if one or both sequencing results were 'Detected'. Conversely a sample had a final sequencing result of 'Not Detected' if both results were 'Not Detected'." This implies a form of 2+0 or 1+1 adjudication model where if either reference method detects CMV, the sample is considered positive, and both must be negative for the sample to be considered negative.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

No, an MRMC comparative effectiveness study was not done. This study focuses on the diagnostic performance of the device itself against a laboratory-based reference method, not on how human readers/clinicians improve with AI assistance.

6. Standalone (Algorithm Only) Performance

Yes, a standalone performance evaluation was done. The Simplexa™ Congenital CMV Direct assay is a real-time PCR assay and its performance was evaluated directly against the Composite Reference Method (CRM) without human-in-the-loop assistance. The reported PPA and NPA values represent the algorithm's standalone performance.

7. Type of Ground Truth Used

The ground truth used was expert consensus on laboratory results, specifically based on a "Composite Reference Method (CRM) utilized two (2) validated PCR followed by bi-directional sequencing assays." This is a highly robust and objective form of ground truth for nucleic acid detection devices, often considered a gold standard in molecular diagnostics.

8. Sample Size for the Training Set

The document does not provide information on the sample size used for the training set. This is typical for submissions of this nature, where the focus is on the validation of the final device/algorithm using a separate, independent test set, rather than details of the developmental (training) phase.

9. How the Ground Truth for the Training Set Was Established

The document does not provide information on how the ground truth for the training set was established, as details about the training phase are not included in this summary.

Ask a specific question about this device