What's the plural form of hyperthyroxinaemia? Here's the word you're looking for.
Answer
The noun hyperthyroxinaemia can be countable or uncountable.
In more general, commonly used, contexts, the plural form will also be hyperthyroxinaemia.
However, in more specific contexts, the plural form can also be hyperthyroxinaemias e.g. in reference to various types of hyperthyroxinaemias
or a collection of hyperthyroxinaemias.