The present invention relates to a method for the detection of a specific disease in a mammal, comprising providing an NMR spectrum of metabolites in a body fluid of an individual of said mammal in which said disease is suspected and comparing said NMR spectrum with a difference profile, comprising a plurality of NMR spectral line positions, which express the normalized difference between one or more NMR spectra of metabolites in a body fluid of one or more healthy individuals of said mammal, and one or more corresponding NMR spectra of metabolites in a corresponding body fluid of one or more individuals of said mammal in which the disease has been diagnosed. The invention also relates to the said difference profile for the detection of a disease in a mammal and to methods for the manufacture thereof. The invention also relates to a biomarker for detection of specific diseases, in particular osteoarthritis, and to the use of that biomarker in detection of osteoarthritis.