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For evaluation of colonic transit in adult and pediatic patients (at least 2 years old) with chronic constipation and used to aid in differentiating slow and normal transit constipation.

The device is intended to be used for evaluation of colonic transit time in patients with chronic constipation and used to aid in differentiating slow and normal transit constipation in adults and pediatric patients (at least 2 years old). Ten (10) radiopaque markers per day are swallowed for six consecutive days. On day seven an abdominal radiograph is taken. Based on the number of retained markers and the position in colonic transit time is calculated and compared to reference values. Both total transit and segmental transit dysfunction in the colon can be evaluated with the device. By dividing the particle dose on day six by taking five (5) markers in the morning and five (5) markers in the evening, the whole range of transit times (slow, normal, rapid) transit can be measured from the radiograph.

The device is a convenience package of radiopaque markers (22% Barium Sulphate, 78% Elastosil® R 401/60 Silicone rubber) placed in vegetarian capsules from cellulose (HPMC, Hydroxypropylmethylcellulose), intended for single patient use. The dimension of the markers is 2x4.5mm (ring-formed markers) and 6x2mm (tube-formed markers). The capsules are packed in a blister pack is placed inside a folding box.

Here's an analysis of the acceptance criteria and the study proving the device meets them, based on the provided FDA 510(k) summary for Transit-Pellets:

It's important to note that this document is a 510(k) clearance, which determines substantial equivalence to a predicate device, rather than a full pre-market approval (PMA) that requires extensive clinical trials to establish de novo safety and effectiveness. Therefore, the "studies" mentioned often refer to comparisons with predicate devices, existing literature, or post-market follow-up, rather than new, large-scale randomized controlled trials.

Acceptance Criteria and Reported Device Performance

The document does not explicitly state formal "acceptance criteria" in a quantitative, measurable format with target performance values (e.g., "sensitivity must be >X%", "specificity must be >Y%"). Instead, the performance is demonstrated by showing substantial equivalence to a legally marketed predicate device (Sitzmarks) and by leveraging existing clinical literature and post-market data.

The key performance aspect for Transit-Pellets is its ability to accurately measure colonic transit time (CTT) and thereby aid in differentiating slow and normal transit constipation. The acceptance is implicitly based on the predicate device's established performance and the demonstration that the subject device performs equivalently and safely, especially for the expanded pediatric population.

Table of Performance Comparison (based on equivalence to predicate):

Study Details:

The document primarily refers to a Post-Market Clinical Follow-Up (PMCF) study as the clinical evidence for the expanded pediatric population. This PMCF study appears to be a literature review combined with a user survey.

1. Sample Size Used for the Test Set and Data Provenance:

   • Literature Review: The PMCF study identified 18 clinical investigations involving similar devices. These studies collectively involved 1054 children and young adults.
   • Data Provenance: The document does not specify the country of origin for these 18 studies. The nature of these studies (retrospective/prospective) is also not explicitly stated, but common for such literature reviews, they could include both types.
   • User Survey (part of PMCF): No specific sample size for the user survey is provided, only that it involved "professional users." Data provenance is implied to be from current users of Transit-Pellets or similar devices, likely international given the company's location (Sweden).

2. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications:

   • Ground Truth for Literature Review: The "ground truth" in the 18 studies would have been established by the methods and clinicians within those individual studies, which are not detailed here. For colonic transit time, the ground truth is typically the radiological assessment of marker distribution and retention by medical professionals (e.g., radiologists, gastroenterologists).
   • Experts for PMCF Literature Review: The document does not explicitly state how many experts reviewed the identified 18 clinical investigations or their specific qualifications for the PMCF literature review itself. It implies a "literature review carried out during the PMCF study," suggesting a regulatory or scientific team conducted the review.
   • Experts for User Survey: "Professional users" were surveyed, but their number and specific qualifications (e.g., pediatric gastroenterologists, radiologists) are not provided.

3. Adjudication Method:

   • Not explicitly described. For the PMCF literature review, it's unlikely a formal adjudication method (like 2+1 or 3+1 for individual case review) was applied since it was a review of aggregate published data, not individual case interpretations.
   • For the original 18 studies, the adjudication methods would vary per study; this document does not provide such detail.

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

   • No, an MRMC study was not done in the context of this 510(k) submission. This is not typically required for a Class II diagnostic device seeking substantial equivalence, especially when expanding an indication based on existing technology and literature. The focus is on the device's inherent ability to measure CTT, not on reader performance improvement with AI assistance.

5. Standalone Performance (Algorithm Only without Human-in-the-Loop Performance):

   • Yes, in essence, the "device" is standalone. Transit-Pellets are passive markers. The "performance" being evaluated is their physical and chemical properties (biocompatibility, radiopacity, mechanical strength) and their ability to be visualized and used by a clinician to manually calculate colonic transit time from an X-ray image. There is no AI component or algorithm-only performance to assess in the typical sense of software as a medical device. The physician interprets the X-ray/fluoroscopy image and calculates CTT based on the marker count and position.

6. Type of Ground Truth Used:

   • The ground truth for measuring colonic transit time is based on radiological imaging (abdominal radiograph or fluoroscopy) and the subsequent manual counting and positional analysis of the radiopaque markers by a clinician. This is a well-established method in gastroenterology.
   • For the safety and effectiveness in the pediatric population, the PMCF study relied on published clinical investigation results (which would have used radiological ground truth) and user feedback.

7. Sample Size for the Training Set:

   • Not applicable in the typical sense of AI/ML training. There is no "training set" for an algorithm, as this device consists of physical markers interpreted by human readers.
   • If viewed in a broad sense, the "training" for the device's design (marker size, material, dosing regimen) comes from decades of clinical practice and research using radiopaque markers for colonic transit studies, which predates this specific device.

8. How the Ground Truth for the Training Set Was Established:

   • Not applicable as there is no specific training set for an algorithm. The principle of "ground truth" in this context refers to the accuracy of colonic transit time measurements derived from the markers. This has been established through clinical consensus and research over time, validating the correlation between marker distribution on X-rays and actual colonic transit physiology.

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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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