{Reference Type}: Letter {Title}: Carbon monoxide rebreathing method is a reliable test to evaluate the red cell mass in polycythaemia. {Author}: Maaziz N;Georges M;Basille D;Gallet M;Gardie B;Diouf M;Garçon L;Girodon F; {Journal}: Br J Haematol {Volume}: 204 {Issue}: 2 {Year}: 2024 02 3 {Factor}: 8.615 {DOI}: 10.1111/bjh.19169