HSN Code 3822 refers to "Diagnostic or laboratory reagents on a backing, prepared diagnostic or laboratory reagents whether or not on a backing, and certified reference materials (excluding compound diagnostic reagents designed to be administered to the patient, blood-grouping reagents, animal blood prepared for therapeutic, prophylactic or diagnostic uses and vaccines, toxins, cultures of micro-organisms and similar products)." This classification code is essential for identifying diagnostic and laboratory reagents for import/export purposes based on their nature, composition, and intended use. Common products under HSN Code 3822 include prepared diagnostic reagents, laboratory reagents on a backing, and certified reference materials. Additionally, the GST rate for diagnostic and laboratory reagents under this code supports accurate trade compliance.