In this study of a large cohort from a tertiary care hospital in a non-endemic area of TB, 0.07% [0.06; 0.09%] of patients presenting with hyponatremia and 0.28% [0.06%; 0.80%] with SIADH, but especially younger patients and patients with high CRP values, were diagnosed with TB. The gene discussed is CRP; the disease is tuberculosis.