Blue sclerae: a common sign of iron deficiency?

169 hospital inpatients were studied to assess the association of blue sclerae with iron-deficiency anaemia. Three observers independently graded the signs of blue sclerae and mucosal pallor as absent, equivocal, definite, or striking. Blue sclerae were seen more often in patients with iron-deficiency anaemia (40/46, 87%) than in those with other anaemias (2/28, 7%; p less than 0.001) or without anaemia (5/95, 5.3%; p less than 0.001). The specificity of blue sclerae in iron-deficiency anaemia was 0.94 with a sensitivity of 0.87. By comparison, mucosal pallor was noted in only 30% of patients with iron-deficiency anaemia, with a specificity of 0.96 and a sensitivity of only 0.20 (p less than 0.001). The presence of blue sclerae was unaffected by age, sex, or colour of iris. Blue sclerae appear to be a good indicator of iron deficiency and should become a regular part of clinical examination.