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ID-FISH Plasmodium Genus Test Kit (PlasG) and ID-FISH Plasmodium falciparum and P. vivax Combo Test Kit (PlasFV) are intended for in vitro diagnostic use in the clinical laboratory for detection of Plasmodium species in human venous whole blood (EDTA) samples from patients suspected of Plasmodium infection. The test kits are intended to aid in the diagnosis of malaria and to aid in the differential diagnosis of P. falciparum and P. vivax infection. The test kits should be used only on samples from patients with a clinical history, signs and symptoms consistent with malaria, and are not intended as a screen for asymptomatic patients.

The ID-FISH Plasmodium Genus Test Kit is a qualitative test for detection of malaria parasites in blood smears. Positive results should be supplemented with the Plasmodium species specific test kit, ID-FISH Plasmodium falciparum and P. vivax Combo Test Kit for identification and differentiation of Plasmodium falciparum and Plasmodium vivax. The results of these test kits should be used in conjunction with other diagnostic test results. Clinical performance has not been established for P. ovale, P. malariae, or P. knowlesi.

The ID-FISH Plasmodium Genus Test Kit (PlasG) and ID-FISH Plasmodium falciparum and P. vivax Combo Test Kit (PlasFV) are fluorescence in situ hybridization (FISH) assays to detect Plasmodium spp. or P. falciparum or P. vivax parasites in thin film blood smears prepared from EDTA venous whole blood samples.

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

Acceptance Criteria and Reported Device Performance

Study Details Proving Device Meets Acceptance Criteria

1. Sample Size and Data Provenance:

   • Reproducibility Test Samples: A panel of 5 contrived samples (1 negative, 2 low positive P.f., 1 moderate positive P.f., 1 low positive P.v., 1 moderate positive P.v.) were used. 180 replicate slides (with 2 smears per slide) were prepared from each sample across two separate sites, totaling 900 slides.
   • Clinical Test Set:
     • Total: 1067 leftover venous whole blood (EDTA) samples.
     • Provenance:
       • Endemic Regions: 917 samples from India (300 sequential), Kenya (395 sequential from multiple sites), and Peru (222 selective enrollment). Patients had malaria-like symptoms.
       • Non-Endemic Region: 150 symptomatic patient samples from the United States.
     • Retrospective/Prospective: Samples were generally collected between 2013 and 2015. The collection method for endemic regions involved "sequential samples (i.e. all comers meeting inclusion criteria)" for India and Kenya, which implies a prospective component for real-world representation, although the term "leftover" suggests they were archived for study. Peru samples were "selectively enrolled" which indicates a retrospective design for balancing positive/negative cases. Non-endemic samples were "all comers," implying a prospective or representative collection.

2. Number of Experts and Qualifications for Ground Truth:

   • Giemsa Microscopy (Comparator/Ground Truth): "pre-defined, expert adjudication by up to three microscopists."
   • Qualifications: The document does not explicitly state the qualifications (e.g., years of experience, board certification) of these microscopists. However, the term "expert adjudication" implies high proficiency.

3. Adjudication Method for the Test Set:

   • Giemsa Microscopy: "pre-defined, expert adjudication by up to three microscopists." This suggests a consensus-based approach (e.g., majority rule, or final decision by a senior expert after initial reads), but the exact "pre-defined" method (e.g., 2+1, 3+1) is not explicitly detailed beyond "up to three."
   • Discrepant Analysis for Clinical Study: PCR testing followed by bi-directional sequencing was used for discrepant analysis between the device results and Giemsa microscopy. This serves as a molecular "tie-breaker" for cases where the human expert consensus diverges from the device.

4. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study:

   • No MRMC comparative effectiveness study was explicitly described in the provided text. The study primarily compares the device's performance to human expert microscopy as a reference standard (standalone performance relative to ground truth), rather than comparing human reader performance with and without AI assistance. The device is a "kit" for performing a FISH assay, observed by operators through a microscope, not an AI interpreting images for humans. So, an MRMC study in the typical AI sense is not applicable here.

5. Standalone Performance (Algorithm Only):

   • Yes, the core of the clinical study evaluates the standalone performance of the ID-FISH Plasmodium Genus Test Kit (PlasG) and the ID-FISH Plasmodium falciparum and P. vivax Combo Test Kit (PlasFV). These are diagnostic kits based on FISH technology, not an automated image analysis algorithm in the AI sense. The "algorithm" here is the chemical reaction and visual interpretation by a human operator, making the performance measurement of the kit itself (its ability to bind to target RNA) rather than an AI algorithm's interpretive accuracy. The results presented in Tables 10-26 directly show the kit's performance (sensitivity, specificity, PPA, NPA) against the Giemsa microscopy gold standard, followed by PCR for discrepant cases.

6. Type of Ground Truth Used:

   • Primary Ground Truth: Expert consensus Giemsa thick and thin smear malaria microscopy.
   • Secondary/Discrepant Ground Truth: PCR testing followed by bi-directional sequencing for discrepant analysis between the device results and Giemsa microscopy. This acts as a higher-level confirmation for cases where the initial human reads and device results don't align.

7. Sample Size for Training Set:

   • The document describes the analytical and clinical validation studies. There is no mention of a separate "training set" as would be typical for machine learning models. This is due to the nature of the device being a laboratory test kit (FISH assay) rather than an AI/ML diagnostic algorithm that requires a training phase. The studies described are for validation of the completed device.

8. How Ground Truth for Training Set was Established:

   • As there's no explicitly mentioned "training set" in the context of an AI/ML model, this question is not directly applicable. If one considers the development of the FISH probes themselves, the "ground truth" would have been established through molecular biology techniques ensuring probe specificity and sensitivity to the target ribosomal RNA sequences. However, the document focuses on the validation of the final kit.

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