(60 days)
The CMV Brite™ Turbo Kit is intended for the qualitative detection of Cytomegalovirus (CMV) lower matrix protein pp65 by indirect immunofluorescence using microscopy in isolated peripheral blood leukocytes obtained from ethylenediaminetetraacetic acid (EDTA) or heparin anticoagulated human peripheral blood. The detection of CMV pp65 in human perpheral blood cells aids in the diagnosis of acute or reactivated CMV infection. This product is not FDA cleared (approved) for use in testing (i.e., screening) of blood or plasma donors.
The CMV antigenemia assay has been developed using a cocktail of two monoclonal antibodies (C10/C11) directed against CMV lower matrix protein pp65(6). The assay uses the C10/C11 cocktail in an indirect immunofluorescence staining of cytospin preparations of peripheral blood leukocytes. The CMV Brite™ Turbo antigenemia assay is completed within two hours of blood collection which saves time and means a rapid answer for the clinician. The CMV Brite™ Turbo method consists of:
- Direct lysis of peripheral blood erythrocytes a.
- Preparation of cytospin slides b.
- Fixation and permeabilization C.
- Indirect immunofluorescence staining using monoclonal antibodies directed d. against CMV pp65 protein
- Reading and evaluation of results e.
The first step in the CMV Brite™ Turbo method involves direct lysis of the peripheral blood erythrocytes(22). Following lysis the leukocytes are cytocentrifuged onto a slide, fixed and permeabilized to allow subsequent detection of CMV pp65 antigen. The presence of the CMV pp65 antigen is detected by the C10/C11 antibody cocktail and visualized by means of a specific secondary FITC-labeled antibody. CMV antigenpositive leukocytes exhibit homogeneous yellow-green polylobate nuclear staining when observed using a fluorescence microscope. The number of CMV antigen-positive cells are counted per duplicate stain.
The whole procedure can be performed in approximately 2 hours. The total analysis time has been shortened by performing direct erythrocyte lysis on whole blood and avoiding dextran sedimentation. Further time has been saved by shortening individual steps in the protocol so that the whole CMV antigenemia procedure has been reduced in time by more than 50%.
Here's a breakdown of the acceptance criteria and study information for the CMV Brite™ Turbo Kit, based on the provided text:
Acceptance Criteria and Reported Device Performance
The provided document specifically compares the CMV Brite™ Turbo Kit to its predicate device, the CMV Brite™ Test Kit, in terms of performance characteristics. The "acceptance criteria" are implied by the performance of the predicate device, which the new device aims to be "as safe, effective, and performs as well as."
| Acceptance Criteria (implied by predicate device performance) | Reported Device Performance (CMV Brite™ Turbo) |
|---|---|
| Sensitivity: 91.0% | Sensitivity: 87.4% |
| Specificity: 99.5% | Specificity: 98.8% |
| Positive Predictive Value: 98.9% | Positive Predictive Value: 92.4% |
| Negative Predictive Value: 95.7% | Negative Predictive Value: 97.9% |
Note: The document states, "The performance characteristics of the CMV Brite™ Turbo Kit are the same as those established for the CMV Brite™ Test Kit." However, the comparative table (Table 1) then lists slightly different numerical values for sensitivity, specificity, and predictive values. This might indicate that "the same" refers to generally comparable performance rather than identical numerical results, or that the table itself is the primary source of the "established" performance for the new device based on its own testing. For the purpose of this response, I'm listing the specific numbers presented in the table for the CMV Brite™ Turbo.
Study Details
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Sample size used for the test set and the data provenance:
- Test Set Sample Size: The document does not explicitly state the sample size used for the test set.
- Data Provenance: The document does not specify the country of origin of the data or whether it was retrospective or prospective.
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Number of experts used to establish the ground truth for the test set and the qualifications of those experts:
- The document does not specify the number of experts or their qualifications for establishing ground truth for the test set. The nature of the device (immunofluorescence staining read by microscopy) implies a human reader, but details about independent review or consensus are missing.
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Adjudication method for the test set:
- The document does not describe any specific adjudication method (e.g., 2+1, 3+1, none) for the test set.
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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, an MRMC comparative effectiveness study was not done. This device is a test kit for laboratory use, involving manual interpretation via fluorescence microscopy, not an AI-assisted diagnostic tool. Therefore, the concept of human readers improving with AI assistance is not applicable here.
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If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:
- No, a standalone algorithm-only performance study was not done. This device is a manual laboratory test kit that requires human interpretation (microscopy of stained cells) to detect CMV pp65 antigen. It is not an algorithm or AI-driven system.
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The type of ground truth used (expert consensus, pathology, outcomes data, etc.):
- The type of ground truth is not explicitly stated. Given the nature of CMV antigenemia testing, the ground truth would typically be established by clinical diagnosis of CMV infection, often supported by other laboratory methods (e.g., PCR, viral culture, or clinical outcomes), or by expert interpretation of the gold standard for CMV antigenemia. The document describes the new device being compared to a "legally marketed device" (CMV Brite™ Test Kit), implying the predicate device serves as a reference, but the ultimate ground truth for both is not detailed.
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The sample size for the training set:
- The document does not mention a "training set" as this is not an machine learning/AI device. The studies described are for validating the performance of a wet laboratory assay.
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How the ground truth for the training set was established:
- Not applicable, as there is no "training set" for this type of device.
§ 866.3175 Cytomegalovirus serological reagents.
(a)
Identification. Cytomegalovirus serological reagents are devices that consist of antigens and antisera used in serological tests to identify antibodies to cytomegalovirus in serum. The identification aids in the diagnosis of diseases caused by cytomegaloviruses (principally cytomegalic inclusion disease) and provides epidemiological information on these diseases. Cytomegalic inclusion disease is a generalized infection of infants and is caused by intrauterine or early postnatal infection with the virus. The disease may cause severe congenital abnormalities, such as microcephaly (abnormal smallness of the head), motor disability, and mental retardation. Cytomegalovirus infection has also been associated with acquired hemolytic anemia, acute and chronic hepatitis, and an infectious mononucleosis-like syndrome.(b)
Classification. Class II (performance standards).