(2 days)
The Non-variola Orthopoxvirus Real-time PCR Primer and Probe Set is intended for the in vitro qualitative presumptive detection of non-variola Orthopoxvirus DNA extracted from human pustular rash specimens and viral cell culture lysates submitted to a Laboratory Response Network (LRN) reference laboratory. The assay detects non-variola Orthopoxvirus DNA, including Vaccinia, Cowpox, Monkeypox and Ectromelia viruses at varying concentrations. This assay does not differentiate Vaccinia virus or Monkeypox virus from other Orthopoxviruses detected by this assay and does not detect Variola virus. Refer to the CDC algorithm, Acute, Generalized Vesicular or Pustular Rash Illness Testing Protocol in the United States for recommended testing and evaluation algorithms for patients presenting with acute, generalized pustular or vesicular rash illness.
Results of this assay are for the identification of non-variola Orthopoxvirus DNA. These results must be used in conjunction with other diagnostic assays and clinical observations to diagnose Orthopoxvirus infection. The assay should only be used to test specimens with low/moderate risk of smallpox exists, viral culture should not be attempted. Negative results obtained with this device do not prection and should not be used as the sole basis for treatment or other patient management decisions.
Use is limited to Laboratory Response Network (LRN) designated laboratories.
The Non-variola Orthopoxvirus Real-time PCR Primer and Probe Set uses a fluorogenic probe, consisting of an oliqonucleotide with a reporter dye (FAM) attached to the 5′ end and a quencher dye (BHQ1) attached at or near the 3′ end. The probe anneals to a specific target sequence located between the forward and reverse primers. During the extension phase of the PCR cycle, the 5' nuclease activity of the Taq polymerase degrades the probe causing the reporter dye to separate from the quencher dye, thereby generating a fluorescent signal. With each cycle, additional reporter dye molecules are cleaved from their respective probes and the fluorescence intensity is monitored during the PCR in real-time. The Taq polymerase used in this assay is inactive at room temperature and is activated by incubation at 95°C, thus minimizing the production of nonspecific amplification products.
Each extracted DNA sample is tested using the Non-variola Orthopoxvirus Real-time PCR Primer and Probe set alonq with an internal control primer and probe set(s) to demonstrate adequate DNA extraction, proper function of common reagents and equipment, and the absence of inhibitory substances.
This document is a 510(k) summary for the Non-variola Orthopoxvirus Real-time PCR Primer and Probe Set, submitted by the Centers for Disease Control and Prevention (CDC). It is a re-submission (K221658) of a previously cleared device (K181205). The document largely states that many aspects of the device are unchanged from the previous submission and directs further inquiries about performance characteristics to the CDC.
Based on the provided text, many of the requested details are not explicitly stated in this FDA summary document. The document refers to an "Original Submission (K181205)" for comparison and states that for most performance characteristics, inquiries should be directed to the CDC. However, based on the information available:
1. A table of acceptance criteria and the reported device performance
The document does not explicitly state "acceptance criteria" in a tabulated format or provide detailed "reported device performance" in this summary. It mentions an "Analytical Limit of Detection (LoD)" and "Analytical Sensitivity and Specificity" studies were performed. It also indicates "Clinical Performance" studies were conducted, but the results for these are not presented here. Given that this is a re-submission with an "Unchanged" intended use and principle of operation, the acceptance criteria and performance would likely be similar to or supported by the original submission (K181205).
2. Sample size used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective)
This information is not explicitly provided in the text. It states that inquiries regarding performance characteristics should be directed to the CDC.
3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g. radiologist with 10 years of experience)
This information is not explicitly provided in the text.
4. Adjudication method (e.g. 2+1, 3+1, none) for the test set
This information is not explicitly provided in the text.
5. 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
This device is a PCR primer and probe set for detecting viral DNA, not an AI-assisted diagnostic device. Therefore, an MRMC comparative effectiveness study involving human readers and AI assistance is not applicable and was not performed.
6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done
This device is a molecular diagnostic assay. Its performance is inherent to the chemical reactions and detection system, and it operates "stand-alone" in the sense that the test result is directly outputted by the instrumentation without human real-time modification of the analytical process. However, human interpretation of the results and clinical context is required as stated in the Indications for Use: "Results of this assay are for the identification of non-variola Orthopoxvirus DNA. These results must be used in conjunction with other diagnostic assays and clinical observations to diagnose Orthopoxvirus infection."
7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.)
The document refers to "identification of non-variola Orthopoxvirus DNA" as the output. The ground truth for such molecular tests typically involves:
- Validated reference strains/samples: For analytical sensitivity and specificity, the ground truth would be precisely known viral DNA concentrations or the known presence/absence of target and non-target organisms.
- Clinical diagnosis/outcome: For clinical performance, the ground truth would be established through a combination of other diagnostic assays, clinical observations, and potentially follow-up outcomes, as implied by the statement "These results must be used in conjunction with other diagnostic assays and clinical observations to diagnose Orthopoxvirus infection."
Specific details are not provided in this summary.
8. The sample size for the training set
This information is not provided in the text. As a PCR diagnostic kit, there isn't typically a "training set" in the machine learning sense. Instead, development involves assay design, optimization, and then validation studies.
9. How the ground truth for the training set was established
Not applicable as there is no "training set" in the machine learning context for this type of device. Assay optimization and validation (which could be considered analogous to "training" and "testing" in a broad sense for a traditional diagnostic) would rely on well-characterized samples with established viral content.
N/A