The present disclosure is directed to methods (e.g., in vitro methods) for detecting the presence of neutralizing antibodies to PTH or PTHrP analog in a sample. The in vitro method comprises the steps of obtaining a sample from a subject; contacting the sample with a cell; measuring cyclic adenosine monophosphate (cAMP) levels; and detecting the presence of neutralizing antibodies when cAMP levels are reduced relative to a negative control sample without neutralizing antibodies. An in vitro method of detecting the presence of neutralizing antibodies in a sample from a subject treated with Abaloparatide, is also provided. Further provided herein is a kit for carrying out the methods described herein comprising components required to carry out the obtaining, contacting, measuring and detecting steps and instructions for use.