An in vitro method of determining the likelihood ratio of an individual having, or obtaining, bacterial vaginosis comprising the steps of: performing an analysis on a sample to determine a quantification level value (IQ1, IQ2) of at least two different species (M1, M2) for bacterial vaginosis; determining limit quantification values (LT1, LT2) for each of said species, wherein said limit quantification value (LT1, LT2) are calculated from a validation study and determining a likelihood ratio value (LH1, LH2) for each of said species by comparing the quantification level value (IQ1, IQ2) with the limit quantification values (LT1, LT2); wherein the method further comprises: determining a quantification level for a first base species; normalizing the quantification level values for each of said other species by subtracting the quantification level value of said first base species from said other quantification level values; through the formula IQ2-IQ1=ΔIQ2; thereby obtaining a normalized quantification level value (ΔIQ2) for each one of the other species; and wherein the determination of a likelihood ratio value (LH1, LH2) for each of said species is performed by comparing said normalized quantification level values (ΔIQ2) with the limit quantification value (LT1, LT2) for each species, and wherein the step of the calculating the likelihood ratio value of bacterial vaginosis is through the following algorithm, wherein six different species other than the first base species are used: LHD = ODDS (disease in general population)* LH2*LH3*LH4*LH5*LH6*LH7. performing an analysis on a sample to determine a quantification level value (IQ1, IQ2) of at least two different species (M1, M2) for bacterial vaginosis; determining limit quantification values (LT1, LT2) for each of said species, wherein said limit quantification value (LT1, LT2) are calculated from a validation study and determining a likelihood ratio value (LH1, LH2) for each of said species by comparing the quantification level value (IQ1, IQ2) with the limit quantification values (LT1, LT2); wherein the method further comprises: determining a quantification level for a first base species; normalizing the quantification level values for each of said other species by subtracting the quantification level value of said first base species from said other quantification level values; through the formula IQ2-IQ1=ΔIQ2; thereby obtaining a normalized quantification level value (ΔIQ2) for each one of the other species; and wherein the determination of a likelihood ratio value (LH1, LH2) for each of said species is performed by comparing said normalized quantification level values (ΔIQ2) with the limit quantification value (LT1, LT2) for each species, determining a quantification level for a first base species; normalizing the quantification level values for each of said other species by subtracting the quantification level value of said first base species from said other quantification level values; through the formula IQ2-IQ1=ΔIQ2; thereby obtaining a normalized quantification level value (ΔIQ2) for each one of the other species; and wherein the determination of a likelihood ratio value (LH1, LH2) for each of said species is performed by comparing said normalized quantification level values (ΔIQ2) with the limit quantification value (LT1, LT2) for each species, and wherein the step of the calculating the likelihood ratio value of bacterial vaginosis is through the following algorithm, wherein six different species other than the first base species are used: LHD = ODDS (disease in general population)* LH2*LH3*LH4*LH5*LH6*LH7.