A method of classifying a subject having idiopathic scoliosis (IS) or at risk of developing IS or a method of determining the risk of developing IS in a subject, wherein the IS is preferably adolescent IS (AIS), comprising: A) a) contacting a cell sample from the subject with i) an agonist of cluster I or cluster II GiPCR； and ii) Pertussis toxin (PXT)； b) determining the cellular response to Gi stimulation； and c) classifying said subject into a IS functional group according to the subject's cellular response profile； or B) a) contacting a cell sample from the subject with an agonist of a cluster II GiPCR； b) determining the cellular response to Gi protein stimulation by cellular impedance； and c) classifying the subject into a IS functional group according to the subject's cellular impedance profile. A corresponding kit is also disclosed. A method of selecting a preventive measure, treatment or follow-up schedule for a subject suffering from IS or at risk of developing IS, wherein the IS is preferably adolescent IS (AIS), comprising classifying the subject using at least one of the method as defined above and classifying the subject in functional groups FG1-FG3 based on levels of OPN, HA,CD44, the frequency a of scoliosis assessment or the prescription of corrective surgery prior to reaching a Cobb's angle of 45 degrees.
