Immunochemistry Diagnostic Device segmentation by application reflects the clinical contexts that drive demand. Clinical chemistry accounts for the largest share, roughly 40 % of total revenue, as hospitals and reference laboratories rely on immuno‑assays for hormone, enzyme, and metabolic marker quantification. The oncology segment follows with about 25 %, powered by the need for tumor‑marker detection (e.g., PSA, CA‑125) and therapy monitoring. Infectious‑disease testing contributes 20 %, encompassing serology for viral, bacterial, and parasitic pathogens, a share that expanded markedly during recent pandemic cycles. Cardiology applications, representing 10 %, focus on cardiac‑troponin and natriuretic‑peptide assays for acute‑care diagnostics. The residual 5 % falls under “others,” including veterinary, environmental, and research‑only uses. Collectively, these application categories shape the overall market size, with the relative weight of each segment informing product‑development priorities and geographic sales strategies. Regional analysis shows North America and Europe dominate the clinical‑chemistry and oncology sub‑segments, while Asia‑Pacific exhibits faster growth in infectious‑disease and point‑of‑care deployments, reinforcing the strategic relevance of application‑driven portfolio allocation.