(90 days)
SERIM Blood Leak Test Strips provide a rapid and convenient means for testing spent dialysate for blood in hemodialysis clinics. The presence of blood in dialysate indicates a leak in the dialysis membrane.
The SERIM Blood Leak Test Strip consists of a 0.2 x 0.2 inch reagent pad attached to one end of a white 0.2 x 3.25 inch polystyrene handle. The reagent pad is immersed into a sample, removed immediately and allowed to react for 60 seconds. Then the reagent pad color is compared to two color blocks on the bottle label. One color block marked Negative is yellow with a few green speckles. If a reagent pad has a similar yellow color the dialysate does not contain significant blood. The second color block is green with small yellow speckles and is marked Positive. A reagent pad with green color equal to or darker than this color block indicates the presence of a significant blood leak.
Here's a breakdown of the acceptance criteria and study detailed in the provided document for the SERIM™ Blood Leak Test Strips:
1. Table of Acceptance Criteria and Reported Device Performance
| Acceptance Criteria | Reported Device Performance |
|---|---|
| Specificity: 100% (no false positives) for dialysis buffer without blood. | 100 negative strip readings (100% specificity) obtained with dialysis buffer without blood. |
| Sensitivity: 100% (all true positives detected) for dialysis buffer containing 1.5 mg/dL hemoglobin. | 100 positive strip readings (100% sensitivity) obtained with dialysis buffer containing non-hemolyzed blood at 1.5 mg/dL hemoglobin. |
| Agreement with predicate device (Chemstrip occult blood test) for 101 dialysate samples (negative for blood leaks). | Both SERIM strips and Chemstrip occult blood test gave negative readings for blood leaks in all 101 dialysate samples. |
| Agreement with predicate device for spiked dialysate samples (33 samples spiked with 1.5 mg/dL hemoglobin). | All 33 spiked samples gave positive blood leak readings with both types of strips (SERIM and Chemstrip). |
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size:
- 100 negative samples (dialysis buffer without blood).
- 100 positive samples (dialysis buffer with 1.5 mg/dL hemoglobin).
- 101 dialysate samples collected at a dialysis clinic.
- 33 of the 101 dialysate samples were spiked with blood.
- Data Provenance: The document does not explicitly state the country of origin, but given the FDA submission, it is likely US-based. The study appears to be a prospective evaluation of the strips against defined standards and collected dialysate samples.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Their Qualifications
The document mentions that "12 participants" used the SERIM Blood Leak Test Strips to test blood standards in "blind studies." It does not specify their qualifications or if they are considered "experts" in the sense of establishing ground truth.
For the ground truth of the blood concentrations (1.5 mg/dL hemoglobin), it was "determined by the cyanmethemoglobin method," which is a laboratory assay. This implies chemical validation rather than expert consensus on visual interpretation.
4. Adjudication Method for the Test Set
The document does not describe an adjudication method for disagreements. The results are presented as direct counts of positive and negative readings. Since it's a diagnostic strip interpreted against a color chart, the "adjudication" (if any) would likely be an intrinsic part of the 12 participants' individual interpretations, though this isn't explicitly detailed.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done
No, a multi-reader multi-case (MRMC) comparative effectiveness study focusing on human readers improving with AI vs. without AI assistance was not done. This study evaluates a diagnostic test strip, which is a standalone device interpreted by a user, not an AI system assisting human readers.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done
Yes, in essence, the study evaluates the SERIM Blood Leak Test Strips as a standalone diagnostic device. The "algorithm" here is the chemical reaction on the strip leading to a color change, which is then visually compared to a reference color chart on the bottle label by the user. The performance reported (specificity and sensitivity) is for this standalone function (device + user interpretation). The "12 participants" are the human-in-the-loop for interpretation, but the focus is on the device's ability to produce the correct color change.
7. The Type of Ground Truth Used
The ground truth used was a combination of:
- Laboratory Assay/Known Concentration: For the 100 positive samples, the hemoglobin concentration of 1.5 mg/dL was "determined by the cyanmethemoglobin method." For the negative samples, it was dialysis buffer without blood, representing a known absence.
- Comparator Device Performance (for clinical samples): For the 101 dialysate samples and the 33 spiked samples, the performance of the SERIM strips was compared to "Chemstrip occult blood strips" (the predicate device). While not a standalone "ground truth" in terms of direct pathology or outcomes data, the agreement with an established, legally marketed equivalent device serves as a strong comparator for substantial equivalence.
8. The Sample Size for the Training Set
The document does not mention a training set for the device. This is a diagnostic test strip that relies on chemical reactions and visual interpretation, not a machine learning or AI-based device that typically requires a training set.
9. How the Ground Truth for the Training Set Was Established
As no training set is mentioned or applicable for this type of device, this question is not relevant to the provided documentation.
§ 876.5820 Hemodialysis system and accessories.
(a)
Identification. A hemodialysis system and accessories is a device that is used as an artificial kidney system for the treatment of patients with renal failure or toxemic conditions and that consists of an extracorporeal blood system, a conventional dialyzer, a dialysate delivery system, and accessories. Blood from a patient flows through the tubing of the extracorporeal blood system and accessories to the blood compartment of the dialyzer, then returns through further tubing of the extracorporeal blood system to the patient. The dialyzer has two compartments that are separated by a semipermeable membrane. While the blood is in the blood compartment, undesirable substances in the blood pass through the semipermeable membrane into the dialysate in the dialysate compartment. The dialysate delivery system controls and monitors the dialysate circulating through the dialysate compartment of the dialyzer.(1) The extracorporeal blood system and accessories consists of tubing, pumps, pressure monitors, air foam or bubble detectors, and alarms to keep blood moving safely from the blood access device and accessories for hemodialysis (§ 876.5540) to the blood compartment of the dialyzer and back to the patient.
(2) The conventional dialyzer allows a transfer of water and solutes between the blood and the dialysate through the semipermeable membrane. The semipermeable membrane of the conventional dialyzer has a sufficiently low permeability to water that an ultrafiltration controller is not required to prevent excessive loss of water from the patient's blood. This conventional dialyzer does not include hemodialyzers with the disposable inserts (Kiil type) (§ 876.5830) or dialyzers of high permeability (§ 876.5860).
(3) The dialysate delivery system consists of mechanisms that monitor and control the temperature, conductivity, flow rate, and pressure of the dialysate and circulates dialysate through the dialysate compartment of the dialyzer. The dialysate delivery system includes the dialysate concentrate for hemodialysis (liquid or powder) and alarms to indicate abnormal dialysate conditions. This dialysate delivery system does not include the sorbent regenerated dialysate delivery system for hemodialysis (§ 876.5600), the dialysate delivery system of the peritoneal dialysis system and accessories (§ 876.5630), or the controlled dialysate delivery system of the high permeability hemodialysis system § 876.5860).
(4) Remote accessories to the hemodialysis system include the unpowered dialysis chair without a scale, the powered dialysis chair without a scale, the dialyzer holder set, dialysis tie gun and ties, and hemodialysis start/stop tray.
(b)
Classification. (1) Class II (performance standards) for hemodialysis systems and all accessories directly associated with the extracorporeal blood system and the dialysate delivery system.(2) Class I for other accessories of the hemodialysis system remote from the extracorporeal blood system and the dialysate delivery system, such as the unpowered dialysis chair, hemodialysis start/stop tray, dialyzer holder set, and dialysis tie gun and ties. The devices subject to this paragraph (b)(2) are exempt from the premarket notification procedures in subpart E of part 807 of this chapter subject to the limitations in § 876.9.