(386 days)
Ahlstrom 226 specimen collection paper is intended to be used as a medium to collect and transport blood specimen spots to a laboratory. The 226 paper will be in the format of a printed card that may be incorporated along with a tear-apart form for demographic information.
Ahlstrom 226 specimen collection paper is designed to provide a uniform surface for the collection of blood spots. A drop of blood is applied to the filter paper and allowed to soak through the paper. The sample is then air dried and sent to a laboratory for further analysis.
This specimen collection paper is made from 100 % pure cotton linters with no wetstrength additives added and conforms to the Recognized Consensus Standard NCCLS LA4-A3.
This device has 4 crucial performance characteristics that can be performed with lysed or intact red blood cells: blood absorption time, blood spot diameter, serum absorption volume, and homogeneity.
Acceptance Criteria and Device Performance for Ahlstrom 226 Specimen Collection Paper
1. Table of Acceptance Criteria and Reported Device Performance
The acceptance criteria for the Ahlstrom 226 Specimen Collection Paper are derived from the Recognized Consensus Standard NCCLS LA4-A3, Blood Collection on Filter Paper for Neonatal Screening Programs; Approved Standard - Third Edition (1997). The device performance was evaluated against these specifications.
| Performance Characteristic | Acceptance Criteria (NCCLS LA4-A3) | Reported Device Performance (Ahlstrom 226) |
|---|---|---|
| Mean blood absorption time | Lysed red blood cells = 5 - 30 seconds | Within acceptable limits |
| Intact red blood cells = 5 - 30 seconds | Within acceptable limits | |
| Mean blood-spot diameter | Lysed red blood cells = no range published | Within acceptable limits |
| Intact red blood cells = 15 – 17mm | Within acceptable limits | |
| Mean serum-absorption volume | Lysed red blood cells = 1.11 - 1.49 µL | Within acceptable limits |
| Intact red blood cells = 1.37 - 1.71µL | Within acceptable limits | |
| Homogeneity | Lysed red blood cells p > 0.05 | p > 0.05 |
| Intact red blood cells p > 0.05 | p > 0.05 | |
| Purity (Manufacturing) | 100% pure cotton fiber with no wet strength additives | Manufactured from 100% pure cotton fiber with no wet strength additives |
| Basis weight | 110 lb +/- 5% per ream (179 g/m2 +/- 5%) | 110 lb +/- 5% per ream (179 g/m2 +/- 5%) (implied by compliance) |
| pH | 5.7 to 7.5 | 5.7 to 7.5 (implied by compliance) |
| Ash % | 0.1% maximum | 0.1% maximum (implied by compliance) |
Note on "Within acceptable limits": The document states that the CDC's report indicated that "the parameters tested were within acceptable limits," and the independent testing laboratory also found their results to be "within acceptable limits" for the specific tests performed (serum absorption volume and blood spot diameter). This implies the device met the numerical ranges specified by NCCLS LA4-A3.
2. Sample Size and Data Provenance
- Test Set Sample Size: Samples of three lots of Ahlstrom 226 specimen collection paper were used for the evaluation.
- Data Provenance: The testing was conducted by two entities:
- The Centers for Disease Control and Prevention Newborn Screening Quality Assurance Program (CDC).
- An independent testing laboratory.
The document does not specify the country of origin of the data, but the CDC is a US-based organization. The study appears to be prospective as it involved testing specific lots of the Ahlstrom 226 paper for regulatory submission.
3. Number of Experts and Qualifications for Ground Truth
- The document does not explicitly state the "number of experts" or their specific "qualifications" in the traditional sense of clinical diagnostic studies (e.g., radiologists).
- However, the testing was conducted by the Centers for Disease Control and Prevention (CDC) Newborn Screening Quality Assurance Program and an independent testing laboratory. These organizations are considered experts in laboratory testing and quality assurance for newborn screening. Their expertise and methods are implicitly accepted as authoritative for establishing ground truth regarding the physical and performance characteristics of the collection paper.
4. Adjudication Method for the Test Set
- The document describes a form of independent verification/comparison rather than a traditional adjudication method.
- Samples from the same three lots tested by the CDC were also sent to an independent testing laboratory. The purpose was to "compare the results for absorption volume and blood spot diameter to the CDC results and to compare lots of material run at different times to ensure consistency over time."
- This suggests that the results from the CDC served as a primary reference, and the independent laboratory's findings provided a confirmation and assessment of consistency. There is no mention of a formal "adjudication" process like 2+1 or 3+1 concensus for disagreeing expert opinions, as the ground truth is established by objective laboratory measurements against a standard.
5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study
- No, an MRMC comparative effectiveness study was not done.
- This device is a specimen collection paper, not a diagnostic imaging or screening algorithm that involves human readers. Therefore, the concept of human readers improving with or without AI assistance is not applicable to this type of device.
6. Standalone (Algorithm Only) Performance
- A standalone performance evaluation was conducted. The entire study focused on the performance of the Ahlstrom 226 specimen collection paper itself (the "algorithm only" in a broader sense of device function) without human-in-the-loop interaction in the performance testing described. The device's physical and functional characteristics were tested directly by laboratory methods.
7. Type of Ground Truth Used
- The ground truth used was based on objective laboratory measurements of the physical and performance characteristics of the filter paper against the recognized consensus standard NCCLS LA4-A3. This standard provides specific numerical ranges and statistical criteria for characteristics like blood absorption time, blood-spot diameter, serum-absorption volume, and homogeneity. The ground truth is essentially defined by these pre-established, industry-accepted performance specifications.
8. Sample Size for the Training Set
- The document does not specify a separate training set sample size.
- This type of device (a filter paper) and the testing described are not based on machine learning or AI models that typically require distinct training and test sets. The evaluation here is a direct performance validation against a standard.
9. How the Ground Truth for the Training Set Was Established
- Since there is no "training set" in the context of machine learning, there is no ground truth established for a training set. The entire evaluation is a validation against pre-defined industry standards (NCCLS LA4-A3), which serve as the "ground truth" for acceptable performance of such devices.
§ 862.1675 Blood specimen collection device.
(a)
Identification. A blood specimen collection device is a device intended for medical purposes to collect and to handle blood specimens and to separate serum from nonserum (cellular) components prior to further testing. This generic type device may include blood collection tubes, vials, systems, serum separators, blood collection trays, or vacuum sample tubes.(b)
Classification. Class II.