Clinical features

• conjunctival pallor ^a

Why?

Conjunctival pallor makes anaemia more likely, but a normal colour cannot rule it out

Patient	Target Disorder and Reference Standard	Diagnostic Test	LR+ (95% CI)	Post-test Probability
in-patient a (pre-test probability: 18%)	severe anaemia (haemoglobin <9.0 g/dl)	pale conjunctivae	4.5 (1.8 to 11)	50%
		borderline conjunctivae	1.8 (1.2 to 2.7)	29%
		normal conjunctivae	0.61 (0.45 to 0.82)	12%

• pale: little or no evidence of red colour on anterior rim which matched the fleshy part of the posterior aspect of the palpebral conjunctiva
• borderline: neither clearly red nor clearly pale or those with one conjunctiva red and the other pale
• normal: full or nearly full redness of the anterior rim