(28 days)
The Creatine Kinase assay is used for the quantitation of creatine kinase in human serum. Measurements of creatine phosphokinase and its isoenzymes are used in the diagnosis and treatment of myocardial infarction and muscle diseases such as progressive Duchenne-type muscular dystrophy.
Creatine Kinase (CK) is an in vitro diagnostic assay for the quantitative determination of creatine kinase activity in human serum. The Creatine Kinase assay is a clinical chemistry assay in which creatine kinase in the sample catalyzes the transfer of a high energy phosphate group from creatine phosphate to ADP. The ATP produced in this reaction is subsequently used to phosphorylate glucose to produce glucose-6-phosphate (G-6-P) in the presence of hexokinase. G-6-P is then oxidized by glucose-6-phosphate dehydrogenase (G-6-PDH) with the concomitant reduction of NAD to NADH. The rate of formation of NADH is monitored at 340 nm and is proportional to the activity of CK in the sample. This reagent also contains AMP and di-(adenosine-5')-pentaphoshate to prevent interference from adenylate kinase.
The Abbott Laboratories Creatine Kinase assay is an in vitro diagnostic device for the quantitative determination of creatine kinase activity in human serum. This 510(k) summary (K981218) submitted in 1998 demonstrates its substantial equivalence to the Roche Cobas Mira Plus Automated Chemistry System CK NAC assay.
1. Table of Acceptance Criteria and Reported Device Performance:
| Performance Characteristic | Acceptance Criteria (Implied by Predicate) | Reported Device Performance |
|---|---|---|
| Correlation Coefficient (with predicate) | High correlation (e.g., >0.95) | 0.9972 |
| Slope (vs. predicate) | Near 1.0 (indicating proportional agreement) | 1.007 |
| Y-intercept (vs. predicate) | Near 0.0 (indicating minimal constant bias) | -8.757 U/L |
| Total %CV (Precision - Level 1) | Low variability | 2.6% |
| Total %CV (Precision - Level 2) | Low variability | 2.3% |
| Linearity/Assay Range | Comparable to predicate | Up to 2,100 U/L |
| Limit of Quantitation (Sensitivity) | Comparable to predicate | 12 U/L |
Note: The acceptance criteria are "implied by the predicate" as explicit thresholds are not provided in the summary. Substantial equivalence is claimed based on the similarity of performance characteristics to the already marketed predicate device.
2. Sample Size Used for the Test Set and Data Provenance:
The document does not explicitly state the specific sample size used for the comparative performance studies or precision studies. It simply mentions that "comparative performance studies were conducted" and "precision studies were conducted." The data provenance (country of origin, retrospective or prospective) is also not specified, which is common for older 510(k) submissions focusing on in vitro diagnostics. However, given it's a clinical chemistry assay, the samples would likely be human serum.
3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications of Those Experts:
Not applicable. For in vitro diagnostic assays like this, "ground truth" for the test set is established by comparative measurements against a well-established and legally marketed predicate device (the Roche Cobas Mira Plus Automated Chemistry System CK NAC assay) using clinical samples. It does not involve human expert adjudication in the same way an imaging or diagnostic AI device would. The performance of the predicate device serves as the reference standard.
4. Adjudication Method for the Test Set:
Not applicable. As described above, the ground truth is established by the predicate device's measurements, not human expert adjudication.
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 is an in vitro diagnostic assay and does not involve human readers interpreting results in a way that would necessitate an MRMC study or an assessment of AI assistance for human readers.
6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) Was Done:
Yes, the studies describe the standalone performance of the Creatine Kinase assay. The stated performance characteristics (correlation, precision, linearity, sensitivity) are inherent to the device itself when processing samples.
7. The Type of Ground Truth Used:
The ground truth for evaluating the Creatine Kinase assay's performance was the measurements obtained from the legally marketed predicate device, the Roche Cobas Mira Plus Automated Chemistry System CK NAC assay. This is a common approach for demonstrating substantial equivalence for in vitro diagnostics, where a new device's accuracy and reliability are compared to an already accepted method.
8. The Sample Size for the Training Set:
Not applicable. This device is a traditional in vitro diagnostic assay, not an AI/ML-based device that requires a training set in the conventional sense. The "training" for such devices involves reagent formulation, instrument calibration, and optimization based on chemical principles and standard analytical practices, typically using reference materials and established methods rather than large datasets of clinical "training" data.
9. How the Ground Truth for the Training Set Was Established:
Not applicable, as there is no training set in the context of AI/ML. The "ground truth" for developing and calibrating such a device would be based on:
- Known concentrations/activities: Using certified reference materials or highly characterized samples with known CK activity.
- Reference methods: Comparing results to established, gold-standard laboratory methods (though the predicate device is used for substantial equivalence, not necessarily the primary "ground truth" for initial development).
- Analytical specifications: Ensuring the chemical reactions and detection mechanisms perform according to established scientific principles and expected analytical performance ranges.
§ 862.1215 Creatine phosphokinase/creatine kinase or isoenzymes test system.
(a)
Identification. A creatine phosphokinase/creatine kinase or isoenzymes test system is a device intended to measure the activity of the enzyme creatine phosphokinase or its isoenzymes (a group of enzymes with similar biological activity) in plasma and serum. Measurements of creatine phosphokinase and its isoenzymes are used in the diagnosis and treatment of myocardial infarction and muscle diseases such as progressive, Duchenne-type muscular dystrophy.(b)
Classification. Class II.