A method comprising the following steps: (a) providing a turbine component comprising a metal substrate having an external surface; and (b) analyzing the external surface by laser plasma spectroscopy to determine whether a metallic coating is present on or absent from the external surface. If a metallic coating is determined to be present on the external surface, the elemental composition, elemental concentration and/or thickness of the metallic coating present on the external surface may be determined (qualitatively and/or quantitatively) by laser plasma spectroscopy. Another method comprises the following steps: (a) providing a turbine component comprising a metal substrate having an external surface which has been subjected to treatment to remove a metallic coating applied to the external surface; and (b) analyzing the treated external surface by laser plasma spectroscopy to determine the degree of removal of the metallic coating from the treated external surface.