PTGDS and medium chain acyl-CoA dehydrogenase deficiency: SP-triggered PGD2 release from PBLs alone or in combination with SP-triggered pLT release offered the most decisive discrimination of MCAD patients from healthy individuals, as the SP-triggered PGD2 levels of all MCAD patients were higher than that of the healthy individuals, with a distinct cut-off value for SP-triggered PGD2 of 616 pg/ml.