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TAPS is an uncommon condition that occurs in identical twins. It results in one twin becoming very anaemic (low blood level), and the other polycythaemic (high blood level). This can occur either on its own, or after laser treatment for TTTS. So far, the best way to treat this condition is still not established, and research is currently underway in order to find this answer.

Due to the rarity of the condition, most research is limited to very small numbers. An international registry has therefore been created that have collected all the cases of TAPS around the world (including cases from our unit), and the outcomes from different methods of treatment established from much larger numbers.

At St George’s, we have also developed criteria for accurately diagnosing TAPS, and have looked into the natural history and outcomes of twins diagnosed with TAPS according to different diagnostic criteria.

Consensus Diagnostic Criteria and Monitoring of Twin Anemia Polycythemia Sequence: A Delphi Procedure