Immediate Test Notification: Chromogranin A (CHROMA)
This situation requires our laboratories to change to a laboratory using a different assay.
Because Chromogranin A assays are not standardized to a common reference material, the numerical values reported by different assays can vary significantly, and results from different methods or kits cannot be used interchangeably.
Based on historical data, the results from the new assay will be substantially higher than seen with the previous test, which is reflected in the higher reference range of the new assay.
- Patients being followed using serial measurements may see an increase in Chromogranin A levels due to the assay change. Any such changes should be interpreted with caution.
- Patients should be tested to re-establish their baseline values with the new assay.
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