The porphyrias are uncommon disorders of haem biosynthesis and their effect
ive management requires prompt and accurate diagnosis. This article describ
es methods for the determination of urinary porphobilinogen, urinary and fa
ecal total porphyrins, and total porphyrins in erythrocytes and plasma that
are suitable for use in non-specialist laboratories. The selection and int
erpretation of these methods, and the indications for further, more special
ised, investigation are discussed.