Explain the Porphyrins in the urine

Porphyrins (a group of compounds containing the porphin structure, four pyrrole rings connected by methine bridges in a cyclic configuration to which a variety of side chains are attached) are the intermediates in haemoglobin synthesis.

In haemolytic anaemia, when the red blood cells are broken down excessively, the body tries to form more red blood cells and consequently the rate of haemoglobin synthesis increases. Excess porphyrins are produced and so are excreted in the urine.