Our new total protein kit allows users an easy normalization of their collagen or hydroxyproline values (as measured with our total collagen or hydroxyproline kits). The advantage of the new kit is that it starts with the same acid hydrolyzate also used for the total collagen and hydroxyproline kits. Time consuming and variable wet or dry weight determination or making of homogenates is no longer necessary. Furthermore the combination of the kits allows the user to determine collagen (hydroxyproline) per mg protein with only a few 10 micrometer tissue sections. Removal of paraffin is not required. This brings existing paraffin tissue collections within reach of collagen analysis.