The DiaSorin 25 OH Vitamin D Total Assay proves to be the leader in the field, offering the most accurate results over all other leading suppliers of assays. It has 100% cross reactivity with 25 OH Vitamin D2 and 100% cross reactivity with 25 OH Vitamin D3. It has minimal interference from any isomer, such as C3 Epimer, and minimal interference from heterophiles . Since 1985, DiaSorin has set the standard in Vitamin D testing. For years the DiaSorin 25-OH Vitamin D RIA