Kidney Output

[JanaZeckser]

My daughter's urologist ordered the Lasix Mag 3 scan.  When he gave me the results her kidney output time had gotten worst.  Can you tell me what is the average kidney output time for a 4 year old girl?

[Stephen Liroff, MD]

Without a Lasix renogram, you probably would not know about an obstruction involving one kidney. A renal ultrasound may give you an idea that the kdney is more obstructed if it appears to show increasing dilatation of the interior of the kidney, but you would need a renogram to confirm this.
S,A,Liroff, M.D.

[JanaZeckser]

Thank you for this information.  Right now our urologist does not think there is an obstruction.  How would I know if there is or if there becomes one?

[Stephen Liroff, MD]

A lasix Mag3 scan is preformed to look for renal obstruction between the kidneys and the bladder. There are many variables between most institutions performing these tests but when having  these done at the same place each time, most of these are eliminated. Ideally the radionucleide   is cleared  from the kidneys  by ten minutes. If the agent (radionuclide)  is not eliminated   by twenty minute the kidiney is considered to be obstructed. The 10-20m minutes “window” is    a “gray zone” and urologists look at other factors such as pain,  progressive changes, blood pressure, kidney substance thickness, to help in evaluating this situation,
Good luck!
S.A.Liroff.M.D.