The porphyrias are disorders of haem biosynthesis which present with acute neurovisceral attacks or disorders of sun-exposed skin. Acute attacks occur mainly in adults and comprise severe abdominal pain, nausea, vomiting, autonomic disturbance, central nervous system involvement and peripheral motor neuropathy. Cutaneous porphyrias can be acute or chronic presenting at various ages. Timely diagnosis depends on clinical suspicion leading to referral of appropriate samples for screening by reliable biochemical methods. All samples should be protected from light. Investigation for an acute attack: • Porphobilinogen (PBG) quantitation in a random urine sample collected during symptoms. Urine concentration must be assessed by measuring creatinine, and a repeat requested if urine creatinine <2 mmol/L. • Urgent porphobilinogen testing should be available within 24 h of sample receipt at the local laboratory. Urine porphyrin excretion (TUP) should subsequently be measured on this urine. • Urine porphobilinogen should be measured using a validated quantitative ion-exchange resin-based method or LC-MS. • Increased urine porphobilinogen excretion requires confirmatory testing and clinical advice from the National Acute Porphyria Service. • Identification of individual acute porphyrias requires analysis of urine, plasma and faecal porphyrins. Investigation for cutaneous porphyria: • An EDTA blood sample for plasma porphyrin fluorescence emission spectroscopy and random urine sample for TUP. • Whole blood for porphyrin analysis is essential to identify protoporphyria. • Faeces need only be collected, if first-line tests are positive or if clinical symptoms persist. Investigation for latent porphyria or family history: • Contact a specialist porphyria laboratory for advice. Clinical, family details are usually required.

Assessment of duodenogastric bile reflux has hitherto been unsatisfactory. An ambulatory system which utilizes the optical properties of bilirubin is examined. Test readings are correlated with the laboratory values for bilirubin in each of a number of physiological solutions. For dilutions of pure bile there was a linear correlation between absorbance and bilirubin concentration (r = 0.93, p < 0.001). In the more acidic environment of gastric juice there was also a linear correlation between absorbance and bilirubin concentration (r = 0.65, p < 0.001), but absorbance values were significantly higher than those of pure bile solutions (F ratio = 130, p < 0.0001). Normal gastric secretions and saliva give low absorbance values (0.02-0.04). Common foodstuffs such as soups, tea and coffee give higher readings and may interfere with bile reflux assessment in a clinical setting. Bilitec 2000 has potential for use as an ambulatory bile reflux monitoring system but consideration should be given to a standard diet or attention must focus on the fasting period.

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We report a case of 33-year-old female with underlying genetic susceptibility for familial porphyria cutanea tarda due to novel UROD variant (c.636 + 2 dupT) unmasked by transient exposure to supraphysiological oestrogen concentrations following a single cycle of successful controlled ovarian stimulation for oocyte retrieval. Use of oral oestrogen in the form of oral contraceptive pills and hormone replacement therapy has been well known to trigger active porphyria cutanea tarda phenotype in susceptible women. However, to date, the emergence of clinically overt porphyria cutanea tarda has not been reported in association with fertility treatment in the literature before.