My father(66 yrs old) done a test and has a result low creatinine. what does it mean? what will be the effect and how it can be cure?

Low Creatinine: Serum creatinine is a laboratory test that is performed as part of routine blood work and to facilitate diagnosis of kidney disease, not supplement used to gain muscle. Low creatinine levels are a sign of reduced muscle mass, which may be caused by disease, debilitation or aging.

Means nothing: Reference ranges are set so that several percent of healthy folks will fall outside at either end.