(50 days)
The Hemochron Jr. Citrate APTT is a unitized microcoagulation test intended to be used in performing a quantitative one-stage Activated Partial Thromboplastin Time (APTT for monitoring low doses of heparin anticoagulation (up to 1.5 units/ml). The test is performed using a citrated whole blood sample on the Hemochron Jr. microcoagulation instruments. The test is intended for use in point of care settings. For In Vitro Diagnostic Use Only
The Hemochron Jr.Citrate APTT test is a self-contained disposable test cuvette, pre-filled with dried reagents required to perform an Activated Partial Thromboplastin Time (APTT) using citrated whole blood in the Hemochron Jr. Whole Blood Microcoagulation Analyzers. The preparation consists of kaolin, phospholipid, stabilizers and buffers. These same components are used in the previous formulation of the citrate APTT. The citrate APTT test can be performed on both the Hemochron Jr. II and Hemochron Jr. Signature Series instruments. The test is intended for point of care use. The instrument draws a precise volume of blood into the test channel of the cuvette. The cuvette contains the APTT reagent formulation. An array of LED's detects the motion of the blood sample/reagent mixtures as it moves through the precision channel. The blood is pumped back and forth until a clot begins to form, obstructing the channel and slowing the flow of the blood sample. The instrument detects a clot when the blood movement decreases below a predetermined rate.
This document describes the Hemochron® Jr. Citrate Activate Partial Thromboplastin Time (APTT) Cuvette, a medical device for monitoring heparin anticoagulation.
Here's the breakdown of the acceptance criteria and study information provided:
1. Table of Acceptance Criteria and Reported Device Performance
The device is a modification of a predicate device, and the primary acceptance criterion appears to be an improved correlation with laboratory APTT plasma results.
| Acceptance Criterion (Implicit) | Reported Device Performance |
|---|---|
| Improved correlation to laboratory APTT Plasma result | The Hemochron Jr. APTT plasma equivalent values were highly correlated to the laboratory plasma citrate APTT values (R=0.88). The correlation equation was y = 0.77x + 8.57. |
| Acceptable precision for normal and heparinized samples (Level I and Level II) | Cuvette Lot 1 - Normal: Day 1: Mean 95 sec, SD 6.5 sec, CV 6.9%; Day 2: Mean 92 sec, SD 2.1 sec, CV 2.3%; Day 3: Mean 86 sec, SD 5.0 sec, CV 5.9%. Total: Mean 91 sec, SD 5.9 sec, CV 6.4%. |
Cuvette Lot 2 - Normal: Day 1: Mean 94 sec, SD 1.0 sec, CV 1.1%; Day 2: Mean 99 sec, SD 5.9 sec, CV 5.9%; Day 3: Mean 90 sec, SD 6.1 sec, CV 6.8%. Total: Mean 95 sec, SD 5.8 sec, CV 6.1%.
(Note: The table provided for "PRECISION DATA" in the document only includes data for "Normal" levels, not "Level II" for heparinized samples, despite mentioning Level II in the descriptive text.) |
| Substantial equivalence to the predicate device | "The technology employed and intended use of the modified Hemochron Jr.Citrate APTT cuvette is substantially equivalent to the Predicate Hemochron Jr. Citrate APTT." |
2. Sample Size Used for the Test Set and Data Provenance
- Sample Size for Test Set: 210 fresh citrated blood samples.
- Data Provenance: The samples were collected from patients undergoing catheterization and angioplasty. While the document doesn't explicitly state the country of origin, the company is based in Edison, NJ, USA, and the FDA review process suggests the data is likely from the United States. The study appears to be prospective in nature, as samples were collected "at the patient bedside" and then analyzed.
3. Number of Experts Used to Establish Ground Truth for the Test Set and Their Qualifications
- This information is not provided in the document. The ground truth for the correlation study was established by a laboratory APTT test performed on an Electra 900 MLA instrument using Dade Actin FSL* APTT reagent. This is a reference method, not an expert consensus.
4. Adjudication Method for the Test Set
- This information is not applicable/provided. The ground truth was established by a laboratory reference method, not by human experts requiring adjudication.
5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study Was Done, and Effect Size
- No, an MRMC comparative effectiveness study was not done. The primary study was a correlation study comparing the device's performance to a laboratory reference method. The device is for coagulation testing, which typically does not involve human readers interpreting results in the same way imaging devices might.
6. If a Standalone (Algorithm Only Without Human-in-the Loop Performance) Was Done
- Yes, a standalone study was done. The described "Summary of Performance Data and Precision" specifically evaluates the performance of the Hemochron Jr. Citrate APTT device itself, comparing its results to a laboratory standard (correlation) and evaluating its consistency (precision) independently. The device provides a quantitative measurement, so human interpretation after the device provides the result is inherent to its use, but the analytical performance of the device was tested in a standalone manner.
7. The Type of Ground Truth Used
- Reference Laboratory Method: The ground truth for the correlation study was established by performing an APTT test on plasma samples using the Dade Actin FSL* APTT reagent on an Electra 900 MLA instrument. This acts as the "gold standard" laboratory method.
8. The Sample Size for the Training Set
- This information is not provided. The document describes a "modified" reagent formulation, implying that development and potentially internal "training" or optimization occurred, but details on a specific training set size for the algorithms or formulation are absent.
9. How the Ground Truth for the Training Set Was Established
- This information is not provided. As the specific training set and its use are not detailed, neither is the method for establishing its ground truth.
§ 864.7925 Partial thromboplastin time tests.
(a)
Identification. A partial thromboplastin time test is a device used for primary screening for coagulation abnormalities, for evaluation of the effect of therapy on procoagulant disorders, and as an assay for coagulation factor deficiencies of the intrinsic coagulation pathway.(b)
Classification. Class II (performance standards).