The laboratory values that you report for the serum creatinine on your husband are not different from each other. These values are within normal laboratory variation for the serum creatinine test. There is a natural loss of kidney function with aging and some of the decline in the estimated glomerular filtration rate (eGFR) can be attributed to natural aging. In general, there is a loss of 1% kidney function per year beyond age 40. This also comes into consideration when evaluating the laboratory testing that you mention. I suggest that you discuss your concerns with your husband’s physician.