Confirmation of organoid's character with the respective organ
Verification of organoids is done by detecting the cellular proteins for particular tissue type using Immunofluorescence. 

For verifying intestinal organoid, apical membrane markers  (villin or alkaline phosphatase) and basolateral markers (E-cadhehrin) are detected by immunofluorescence. Transporters present in intestinal membranes are also displayed on organoids.  The peptide transporter PEPT1 and the glucose transporter SGLT1 are located on apical membrane, and the glucose transporter GLUT2 is present on basolateral membrane. So, these proteins can also be used as markers for verifying intestinal cells.

Via:  


https://www.nature.com/articles/srep16831
https://www.ncbi.nlm.nih.gov/pubmed/19329995