How many letters does the top answer for “of or relating to the formation of red blood cells” have?

The most common answer is erythropoietic (14 letters).

Crossword clue: of or relating to the formation of red blood cells

1 answer found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

erythropoietic 14 letters wn-def

of or relating to the formation of red blood cells

a deficiency of red blood cells 50% similar → anaemia, anemia

agglutination of red blood cells 50% similar → haemagglutination, hemagglutination

pertaining to the formation of blood or blood cells 50% similar → haematopoietic, haemopoietic, hematopoietic