(49 days)
Sigma Diagnostics ACCUCOLOR™ Antithrombin III (AT-III) is used to determine the level of antithrombin III (a substance which acts with the anticoagulant heparin to prevent blood clots) in plasma. The determination is used to monitor the administration of heparin in the treatment of thrombotic disorders. The determination may also be used to aid in the diagnosis of a congenital deficiency of antithrombin III.
Antithrombin III (ATIII) is the major inhibitor of plasma thrombin and factor Xa. It is also an important inhibitor of activated factors IXA., Xla, and Xlla. The inhibitory activity of ATIII towards thrombin is greatly increased (2-3 orders of magnitude) in the presence of heparin. In the present two-stage method, thrombin is added to a plasma dilution containing antithrombin III in the presence of LMW heparin. After an initial incubation period (stage 1) residual thrombin is determined with a thrombin-specific chromogenic substrate (stage 2). The residual thrombin activity is inversely proportional to the antithrombin III concentration. The use of bovine thrombin and low heparin levels reportedly reduce the interference of HCII in amidolytic assays. Proprietary formulations used in the manufacture of this ATIII assay have lowered the interference from HCII to a level where discrimination between normal and abnormal levels is similar to that achieved by factor Xa based ATIII assays.
The provided text describes the "Sigma Accucolor Antithrombin III Assay Kit (CRS117A)" and its substantial equivalence determination. Here's a breakdown of the requested information based on the provided document:
1. Table of Acceptance Criteria and Reported Device Performance
The document does not explicitly state "acceptance criteria" in a typical quantitative pass/fail format. Instead, it demonstrates performance through comparative studies with predicate devices and precision studies.
| Performance Metric | Acceptance Criteria (Implied) | Reported Device Performance (CRS117A) |
|---|---|---|
| Correlation with Diapharma Coamatic assay (MLA-1000C) | High correlation (e.g., >0.90) | Correlation coefficient (r) = 0.98; Equation: y = 0.91x₁ + 7.85 |
| Correlation with Sigma CRS105A assay | High correlation (e.g., >0.90) | Correlation coefficient (r) = 0.93; Equation: y = 1.03x₂ - 2.3 |
| Within-run CV (Precision) | Low (e.g., |
§ 864.7060 Antithrombin III assay.
(a)
Identification. An antithrombin III assay is a device that is used to determine the plasma level of antithrombin III (a substance which acts with the anticoagulant heparin to prevent coagulation). This determination is used to monitor the administration of heparin in the treatment of thrombosis. The determination may also be used in the diagnosis of thrombophilia (a congenital deficiency of antithrombin III).(b)
Classification. Class II (performance standards).