A new study published in Polski Merkuriusz Lekarski assessed a multiorgan dysfunction in adult patients after Fontan operation in long term follow up in comparison with healthy controls. This study included 54 patients after Fontan procedure as well as 30 controls. It was observed that Fontan patients had a statistically significant higher level of red blood cell counts RBC hemoglobin Hb hematocrit Ht and red blood cell distribution width RDW as compared to the control group. In contrast PLT platelets count level was statistically lower in the Fontan group. Hepatic parameters in Fontan patients were statistically higher. Whereas other parameters such as alpha fetoprotein AFP total protein and albumin level did not statistically differ. In addition 9 patients were diagnosed with protein losing enteropathy PLE . Meanwhile there was no difference in serum creatinine and uric acid levels between Fontan patients and control group. On the other hand cystatin C level was significantly higher in Fontan group than the controls. Furthermore 7 Fontan patients had abnormal microalbumin creatinine ratios. Urine testing preformed in 30 Fontan patients established 23 cases with hematuria while proteinuria was detected in 13 cases and urobilinogen in 7 . Dysfunction of the thyroid gland was found in 30 of patients after Fontan operation 7 in the control group . Moreover among disorders of the thyroid gland 13 of patients were diagnosed with hyperthyroidism 54 with subclinical hypothyroidism and 33 with hypothyroidism. From the findings it was concluded that adult patients after Fontan procedure in long term follow up are exposed to multi organ complications including hematological liver kidney and thyroid dysfunctions.