The study also assessed the use of alternative methods for measuring Lf. Participants were asked to determine the Lf value of the candidate standard using an Enzyme Linked Immunosorbent Assay (ELISA) established at NIBSC, or other suitable in-house method. 10 laboratories performed ELISA according to the NIBSC protocol, 1 laboratory performed flocculation using laser-light scattering according to an in-house protocol, and 1 laboratory performed another in-house ELISA. Results suggest these methods may provide suitable alternatives to the Ramon flocculation test, subject to validation, and that the new standard could act as a suitable reference preparation in these methods.