The concerning case of Swiss expat Theo Zwahlen points to a need for Thailand to seriously reevaluate the logic behind its blood donation criteria. The 25-year-old collapsed on Monday from heatstroke and rhabdomyolysis close to the finish line of a marathon under the scorching sun on Koh Chang in Chanthaburi province. Mr Zwahlen has O- blood, one of the rarest blood types in Thailand. In order to recover his kidney function, multiple dialyses are needed — and for him, one dialysis requires several bags of O- platelets — something the national blood bank at the Thai Red Cross is currently in sh…