All new patients with hypertension should be screened with a history, physical examination, and laboratory inves- tigations, as recommended in Section 7, before initiation of treatment. Secondary hypertension can underlie severe elevation of BP, pharmacologically resistant hypertension, sud- den onset of hypertension, increased BP in patients with hypertension previously controlled on drug therapy, onset of diastolic hypertension in older adults, and target organ damage disproportionate to the duration or severity of the hypertension. Although secondary hypertension should be suspected in younger patients (<30 years of age) with elevated BP, it is not uncommon for primary hypertension to manifest at a younger age, especially in blacks,S5.4-2 and some forms of secondary hypertension, such as renovas- cular disease, are more common at older age. Many of the causes of secondary hypertension are strongly associated with clinical findings or groups of findings that suggest a specific disorder. Figure 3 is an algorithm on screening for secondary hypertension. Table 13 is a detailed list of clinical indica- tions and diagnostic screening tests for secondary hyperten- sion, and Table 14 is a list of drugs that can induce secondary hypertension. Recommendation-Specific Supportive Text 1. The causes of secondary hypertension and recommend- ed screening tests are provided in Table 13, and drugs that can induce secondary hypertension are provided in Table 14. 2. Diagnosis of many of these disorders requires a complex set of measurements, specialized technical expertise, and/ or experience in data interpretation. Similarly, specific treatment often requires a level of technical training and experience. 5.4.1. 