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IntraMarX Radiopaque Markers is a diagnostic test indicated for assisting in the evaluation of colonic motility in patients with severe constipation, as diagnosed by a healthcare professional, but otherwise negative GI evaluations. For use in adult only, IntraMarX Radiopaque Markers is dispensed by physicians to patients for oral intake.

The IntraMarX capsule can be used for the diagnosis of many GI conditions, including chronic constipation, colonic inertia, hypomotility and outlet delay. Each of the IntraMarX capsules contains 24 tiny radiopaque rings within the capsule shell. The capsule is swallowed by the direction of physician. As this capsule moves through the digestive system, the capsule shell will dissolve and leave the rings in the GI tract of the patient; which will show up later during an X-ray scan. Five days after swallowing the capsule, a single scan of the abdomen will be taken to see the location of the rings and how many are left in the GI tract of the patient. The physician will make evaluations based on the rings remaining and make a diagnosis of GI conditions of the patient.

The provided text describes the submission for FDA clearance of the "IntraMarX Radiopaque Markers" device (K191087) and compares it to a predicate device, the "SITZMARKS Capsule" (K181750).

However, the document does not contain specific acceptance criteria for "device performance" in terms of clinical outcomes, nor does it present a detailed study that proves the device meets such criteria in a comparative effectiveness manner (e.g., against human readers or other diagnostic methods). Instead, it focuses on demonstrating substantial equivalence to a predicate device through non-clinical performance data (material safety, physical properties, etc.).

Here's an analysis based on the available information, noting what's present and what's missing:

1. Table of Acceptance Criteria and Reported Device Performance

The document does not explicitly state quantitative acceptance criteria for clinical performance (e.g., sensitivity, specificity, accuracy in diagnosing colonic motility issues) and thus does not report device performance against such criteria. The reported "performance" falls under non-clinical testing for safety and basic functionality.

2. Sample size used for the test set and the data provenance

The document does not describe a clinical "test set" in the context of diagnostic accuracy for colonic motility. All listed tests are non-clinical, focusing on material and physical properties of the device itself. Therefore, information on sample size and data provenance (country, retrospective/prospective) related to a clinical test set is not provided.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts

Not applicable. As no clinical test set for diagnostic performance is described, there's no mention of experts establishing ground truth for such a set.

4. Adjudication method for the test set

Not applicable. No clinical test set needing adjudication is described.

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

Not applicable. This device is a passive radiopaque marker, not an AI software. Therefore, an MRMC study related to AI assistance is not relevant or described.

6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done

Not applicable. This is a physical medical device, not an algorithm.

7. The type of ground truth used

For the non-clinical tests, the "ground truth" is defined by the specific parameters and requirements of the cited ISO, ASTM, USP, and ICH standards/protocols. For example:

• Cytotoxicity: Ground truth is whether cell viability falls below a certain threshold when exposed to device materials.
• Radiopacity: Ground truth is whether the markers are visible on X-ray according to the specified standard.
• Heavy metal testing: Ground truth is whether heavy metal levels are within established safe limits.

8. The sample size for the training set

Not applicable. This device is not an AI algorithm that requires a training set.

9. How the ground truth for the training set was established

Not applicable. This device is not an AI algorithm.

Summary of Device and Approval Context:

The "IntraMarX Radiopaque Markers" device is a diagnostic aid consisting of capsules containing radiopaque rings. Patients swallow the capsule, and after five days, an X-ray of the abdomen is taken to observe the remaining rings in the GI tract. Physicians interpret the location and number of rings to evaluate colonic motility in patients with severe constipation.

The FDA clearance (K191087) is based on demonstrating substantial equivalence to a previously cleared predicate device, the "SITZMARKS Capsule" (K181750). This means the applicant showed that their device has the same intended use and similar technological characteristics, and that any differences do not raise new questions of safety or effectiveness. The core of this demonstration relies entirely on the non-clinical performance data listed above, proving the physical and biological safety of the marker material and its radiopacity. There is no mention of new clinical studies on diagnostic accuracy for this submission. The effectiveness is presumed to be equivalent to the predicate device, which itself would have had to demonstrate effectiveness.

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