How can I optionally pluralize the word "diagnosis" in writing?

I'm building a web form and am looking to label a check box list used to select one or more diagnoses. I want to label this list in a way that indicates to the user that they may select one or more items.

If it were a list of cars, the label would read "Car(s)". The 's' in parentheses indicates that they may select multiple cars but it's not necessary.

How would I do the same for the word diagnosis? My first thought was "Diagnosis(es)". Is this correct?

Solution 1:

I agree that Diagnosis(es) is awkward...I would suggest using the form that represents the most common usage: "Diagnoses" if there are usually multiple diagnoses, and "Diagnosis" if one diagnosis is the norm.