What does it mean if your creatinine levels are decreasing?

Decreased muscle: Since creatinine is generated by muscle, a decrease in creatinine usually means that muscle mass is decreasing. Other causes include improvement of an underlying kidney disease, overhydration and fluid retention, or the early stages of diabetic kidney disease. Lastly, if different labs were used to check blood work, a decrease in creatinine may reflect differences in the labs and reference range.

Short-term factors: Creatinine is affected by protein intake and hydration, both are factors that can be changed easily and affect the result. Have your test repeated. It is the baseline and trend that are important.