To respond to the need of objective screening tools for motor speech disorders (MSD), we present the screening version of a speech assessment protocol (MonPaGe-2.0.s), which is based on semi-automated acoustic and perceptual measures on several speech dimensions in French. We validate the screening tool by testing its sensitivity and specificity and comparing its outcome with external standard assessment tools. The data from 80 patients diagnosed with different types of mild to moderate MSD and 62 healthy test controls were assessed against the normative data obtained on 404 neurotypical speakers, with Deviance Scores computed on seven speech dimensions (voice, speech rate, articulation, prosody, pneumophonatory control, diadochokinetic rate, intelligibility) based on acoustic and perceptual measures. A cut-off of the MonPaGe total deviance score (TotDevS) >2 allowed MSD to be diagnosed with specificity of 95% and an overall sensitivity of 83.8% on all patients pulled, reaching 91% when very mildly impaired patients were excluded. A strong correlation was found between the MonPaGe TotDevS and an external composite perceptual score of MSD provided by six experts. The MonPaGe screening protocol has proven its sensitivity and specificity for diagnosing presence and severity of MSD. Further implementations are needed to complement the characterization of impaired dimensions in order to distinguish subtypes of MSD.