Method for detecting a target moiety in a sample of biological specimens by: a) providing at least one conjugate with the general formula X n - P - Y m, with X is a fluorescent moiety, Y an antigen recognizing moiety, n, m are integers between 1 and 100 and P is a spacer comprising polyethyleneglycol according to general formula I (R 7 CH 2 CHR 5 O)-(CR 1 R 2 CR 3 R 4 O) o -(CH 2 CHR 6 R 8) Wherein R1 to R8 are independently H or a branched or a linear oligomer of ethylene glycol with at least 1 and a maximum of 20000 repeating units or a covalent bond to Y or X, with the provisio that at least two of R1 to R8 are covalent bonds to Y or X and o is an integer of 1 - 500 b) contacting the sample of biological specimens with at least one conjugate, thereby labeling the target moiety recognized by the antigen recognizing moiety Y with the conjugate c) exiting the labelled target moieties with light having a wavelength within the absorbance spectrum of fluorescent moiety X d) detecting the labelled target moieties by detecting the fluorescence radiation emitted by the fluorescent moiety and e) degrading the fluorescent moiety X of the labelled target moieties by irradiating the conjugate with light having a wavelength within the absorbance spectrum of fluorescent moiety X for a time sufficient to deliver enough energy to reduce the fluorescence radiation emitted by the fluorescent moiety at least by 75% of the initial fluorescence radiation characterized in that the conjugate is a compound according to the general formula II: with Z = at least one fluorescent moiety X and at least one antigen recognizing moiety Y; and p is an integer ranging from 2 to 500 or that the conjugate is a compound according to the general formula III: with Z = at least one fluorescent moiety X and at least one antigen recognizing moiety Y; and p is an integer ranging from 2 to 500. a) providing at least one conjugate with the general formula X n - P - Y m, with X is a fluorescent moiety, Y an antigen recognizing moiety, n, m are integers between 1 and 100 and P is a spacer comprising polyethyleneglycol according to general formula I (R 7 CH 2 CHR 5 O)-(CR 1 R 2 CR 3 R 4 O) o -(CH 2 CHR 6 R 8) Wherein R1 to R8 are independently H or a branched or a linear oligomer of ethylene glycol with at least 1 and a maximum of 20000 repeating units or a covalent bond to Y or X, with the provisio that at least two of R1 to R8 are covalent bonds to Y or X and o is an integer of 1 - 500 Wherein R1 to R8 are independently H or a branched or a linear oligomer of ethylene glycol with at least 1 and a maximum of 20000 repeating units or a covalent bond to Y or X, with the provisio that at least two of R1 to R8 are covalent bonds to Y or X and o is an integer of 1 - 500 b) contacting the sample of biological specimens with at least one conjugate, thereby labeling the target moiety recognized by the antigen recognizing moiety Y with the conjugate c) exiting the labelled target moieties with light having a wavelength within the absorbance spectrum of fluorescent moiety X d) detecting the labelled target moieties by detecting the fluorescence radiation emitted by the fluorescent moiety and e) degrading the fluorescent moiety X of the labelled target moieties by irradiating the conjugate with light having a wavelength within the absorbance spectrum of fluorescent moiety X for a time sufficient to deliver enough energy to reduce the fluorescence radiation emitted by the fluorescent moiety at least by 75% of the initial fluorescence radiation the conjugate is a compound according to the general formula II: with Z = at least one fluorescent moiety X and at least one antigen recognizing moiety Y; and p is an integer ranging from 2 to 500 or that the conjugate is a compound according to the general formula III: with Z = at least one fluorescent moiety X and at least one antigen recognizing moiety Y; and p is an integer ranging from 2 to 500.