Was the levels in your blood also checked?
Was the creatinine clearance, a measure of kidney function, calculated?
If so, are they normal?
Thank you for the additional information.
The creatinine and urea are primarily used as a measure of kidney function, but if there is kidney disease, the level of these labs will increase. In general, the creatinine is made by the normal metabolic activity in the muscles and released into the blood stream then filtered by the kidneys and excreted into the urine. If the kidneys are not functioning properly, then the level in the blood increases until the level is sufficient to allow for the creatinine to be cleared at the same rate as the production. In steady state, the total amount of creatinine in the urine over 24 hours will equal the amount of creatinine produced by the muscles. The urea is similarly metabolized, but is produced by any tissue that metabolizes protein, so is largely formed by the muscles, but is produced by other tissues as well.
In your case the total amount of creatinine and urea is low and suggests that there is a decreased production of creatinine and urea. The low serum creatine is another name for creatinine in the blood, but the level is only slightly low. In general, a low creatinine and urea level is not concerning, and certainly not as concerning as an elevated creatinine and urea. The most common cause of this is in a person with lower muscle mass. Therefore, if it is desired to correct the levels, the appropriate step would be muscle building exercises to increase muscle mass.
The fact that you are drinking a large amount of fluids will decrease the concentration of the creatinine and urea in the urine, although it would not decrease the total amount of creatinine and urea over 24 hours. It also will cause the low specific gravity. None of these are concerning. Drinking a large amount of fluids may be concerning if it affects the level of electrolytes in the blood, but if there are no other abnormalities in lab work, then there is no concern about the drinking of large amount of fluids.
These findings do not explain the reason for the need to drink large amounts of fluid. The evaluation of the water drinking requires that there be blood work of the electrolytes, as the body handles water and electrolytes together. Abnormal electrolytes may be related to chronic heart, liver, thyroid, or adrenal disease, although the electrolytes, chemistry profile, and findings on physical examination would guide the next step in the evaluation.