Abstract: Reference membrane components are either pre-labeled or labeled during assays for purposes of normalizing signals associated with binding or functional assays employing G-protein coupled receptor microarrays. A reference component may be included in a membrane in which the target GPCR is embedded or may be present in another membrane printed in conjunction with the target membrane on a microspot. Or, a GPCR microarray may be pre-labeled by incorporating a label on an exposed substrate in a defect in the printed microspot.