Substances or compounds used in laboratory tests to cause a chemical reaction that detects or measures a target — such as glucose, cholesterol, hormones, or pathogens. Reagents are the core consumables in clinical chemistry, haematology, immunology, and microbiology labs. They are supplied in kits matched to specific analyser platforms, with each kit containing precisely calibrated concentrations to ensure consistent, reproducible results.

High-purity chemical compounds used in the formulation, compounding, and quality testing of medicines. In hospital pharmacies and research labs, pharmaceutical-grade chemicals are used to prepare intravenous solutions, compound specialty drugs, and conduct stability or potency testing. They must meet strict pharmacopoeial standards — such as BP (British Pharmacopoeia), USP, or EP — to ensure they are safe for use in or near patients.

Pre-prepared liquid formulations of reagents, supplied at defined concentrations and pH levels, ready for immediate use in diagnostic or research workflows. These include buffers (to maintain stable pH during reactions), wash solutions (to remove unbound material in immunoassays), diluents (to dilute patient samples to the correct working range), and substrate solutions (that produce a colour change to indicate a positive reaction). Correct storage — usually refrigerated — is critical to maintaining their potency.

Specialised liquid formulations used in specific diagnostic tests to confirm the presence or absence of a particular substance, organism, or condition. Examples include glucose tolerance test solutions (oral fluid to trigger a metabolic response), urine dipstick reagent pads, blood grouping sera (to identify ABO and Rh blood types), coagulation reagents (to assess clotting ability), and culture media solutions (to grow and identify bacteria). Each is designed for a single, well-defined clinical purpose.

Specially prepared materials — usually stabilised human serum or plasma with known analyte concentrations — run alongside patient samples to verify that an analyser is performing correctly. They are supplied at two or three levels (low, normal, high) to check accuracy across the full reportable range. Results outside acceptable limits trigger investigation before any patient results are released. QC materials are a regulatory requirement in all accredited clinical laboratories and form the foundation of ISO 15189 compliance.