Use of (i) an anti-CD3 antibody, (ii) an anti-CD56 antibody, (iii) an anti-CD14 antibody, (iv) an anti-CD38 antibody, (v) an anti-CD45 antibody, (vi) an anti-CD90 antibody, (vii) an anti-CD135 antibody, (viii) an anti-CD10 antibody, (ix) an anti-CD11c antibody, (x) an anti-CD19 antibody, (xi) an anti-CD34 antibody, (xii) an anti-CD45RA antibody, (xiii) an anti-CD7 antibody, (xiv) an anti-CD71 antibody, (xv) an anti-CD41/CD61 complex antibody or an anti-CD41 antibody and/or an anti-CD61 antibody (xvi) an anti-CD33 antibody and/or an anti-CD66b antibody, for identifying hematopoietic cell subtypes in an isolated sample, determining the relative frequency of hematopoietic cell subtypes in an isolated sample and/or quantifying the number of cells within hematopoietic cell subtypes in an isolated sample, wherein each of (i) to (xvi) is labelled with a different fluorochrome, wherein when (xvi) is an anti-CD33 antibody and an anti-CD66b antibody, the anti-CD33 antibody and anti-CD66b are labelled with the same fluorochrome, and wherein when (xv) is an anti-CD41 antibody and an anti-CD61 antibody, the anti-CD4 antibody and the anti-CD61 antibody are labelled with the same fluorochrome.