An elevated concentration of chromogranin A (CgA) in blood serum indicates a level above the established reference range defined by the testing laboratory. These reference intervals vary depending on the assay used and the patient population studied. Therefore, a result deemed “high” is relative to the specific lab’s normal values, often expressed in nanograms per milliliter (ng/mL) or micrograms per liter (g/L). As an example, a lab might consider values exceeding 100 ng/mL to be elevated, but this threshold should be interpreted in the context of the individual’s clinical presentation.
Quantifying CgA levels is crucial in the diagnosis and monitoring of neuroendocrine tumors (NETs). Many NET cells secrete CgA, making it a useful biomarker. Elevated levels can assist in identifying the presence of a NET, assessing tumor burden, and monitoring response to therapy. Historically, CgA was recognized as a potential marker for NETs in the 1980s, and its clinical utility has expanded with advancements in assay technologies and increased understanding of its secretion patterns.
