Iron‐dependent oxidative reactions in β‐thalassaemic erythrocyte membranes are involved in premature cell removal and anaemia. We studied 22 β‐thalassaemia intermedia patients (i) to assess if membrane iron accumulation influences the oxidative damage to thalassaemic cells, and (ii) to see whether the mechanisms of haemoglobin destabilization described in vitro have indicators in circulating erythrocytes. Serum non‐transferrin‐bound iron as potentially toxic iron for erythrocytes was also evaluated. Membrane‐bound free iron significantly correlated to bound haemichromes, suggesting a causal relation, but was poorly related to serum non‐transferrin iron, which seems to contribute little to damage from outside the cells. The spleen played an important role in the removal of cells with more membrane iron.

Porphyrias are a group of diseases that are clinically and genetically heterogeneous and originate mostly from inherited dysfunctions of specific enzymes involved in heme biosynthesis. Such dysfunctions result in the excessive production and excretion of the intermediates of the heme biosynthesis pathway in the blood, urine, or feces, and these intermediates are responsible for specific clinical presentations. Porphyrias continue to be underdiagnosed, although laboratory diagnosis based on the measurement of metabolites could be utilized to support clinical suspicion in all symptomatic patients. Moreover, the measurement of enzymatic activities along with a molecular analysis may confirm the diagnosis and are, therefore, crucial for identifying pre-symptomatic carriers. The present review provides an overview of the laboratory assays used most commonly for establishing the diagnosis of porphyria. This would assist the clinicians in prescribing appropriate diagnostic testing and interpreting the testing results.