Clinical Stage 1 Asymptomatic Persistent generalized lymphadenopathy	Clinical Stage 4 HIV wasting syndrome Pneumocystis pneumonia Recurrent bacterial pneumonia Chronic herpes simplex infection (orolabial, genital or anorectal) of more than one month’s duration or visceral at any site Oesophageal candidiasis (or candidiasis of trachea, bronchi or lungs) Extrapulmonary tuberculosis Kaposi’s sarcoma Cytomegalovirus infection (retinitis or infection of other organs) Central nervous system toxoplasmosis HIV encephalopathy Extrapulmonary cryptococcosis, including meningitis Disseminated non-tuberculous mycobacterial infection Progressive multifocal leukoencephalopathy Chronic cryptosporidiosis Chronic isosporiasis Disseminated mycosis (coccidiomycosis or histoplasmosis) Recurrent septicaemia (including non-typhoidal Salmonella) Lymphoma (cerebral or B-cell non-Hodgkin) Invasive cervical carcinoma Atypical disseminated leishmaniasis Symptomatic HIV-associated nephropathy or symptomatic HIV-associated cardiomyopathy
Clinical Stage 2 Unexplained§ moderate weight loss (>10% of presumed or measured body weight)|| Recurrent upper respiratory tract infections (sinusitis, tonsillitis, otitis media and pharyngitis) Herpes zoster Angular cheilitis Recurrent oral ulceration Papular pruritic eruptions Seborrhoeic dermatitis Fungal nail infections
Clinical Stage 3 Unexplained§ severe weight loss (>10% of presumed or measured body weight)|| Unexplained‡ chronic diarrhoea for longer than one month Unexplained‡ persistent fever (above 37.5°C intermittent or constant for longer than one month) Persistent oral candidiasis Oral hairy leukoplakia Pulmonary tuberculosis (current) Severe bacterial infections (such as pneumonia, empyema, pyomyositis, bone or joint infection, meningitis or bacteraemia) Acute necrotizing ulcerative stomatitis, gingivitis or periodontitis Unexplained§ anaemia (<8 g per litre), neutropaenia (<0.5 × 109 per litre) and/or chronic thrombocytopaenia (<50 × 109 per litre)

^*Data from REF. 45.

^‡Some additional specific conditions can also be included in regional classifications, such as the reactivation of American trypanosomiasis (meningoencephalitis and/or myocarditis) in the WHO Region of the Americas, and penicilliosis in Asia.

^§Unexplained is used when the condition is not explained by other conditions.

^||Assessment of body weight among pregnant woman needs to consider the expected weight gain of pregnancy.