Homogentisic acid urine

Specimen:

Random urine.

Method:

Qualitative colour test, colorimetry, HPLC.

Reference Interval:

Not detected.

Application:

Diagnosis of alkaptonuria. Patients present with dark pigmentation of sclerae and ear cartilage, early osteoarthritis of hips (with darkly pigmented cartilage). Their urine contains a reducing substance that is not glucose and the urine characteristically darkens on standing.

Interpretation:

An increased level is diagnostic of alkaptonuria.

Reference:

Bory C et al. Clin Chim Acta. 1990; 189: 7-11.