Re: Creatinine bioassay

[BergerIEM@AOL.COM]

Joel:



The dosimetric evaluations we use for assessing intakes of uranium require an 

understanding of the quantity of radioactive material excreted over a 24-hour 

period.  The only real way of doing this is to collect an individual's urine 

for 24 straight hours.  And while there are ways of "simulating" a 24-hour 

collection of urine, some correction to the measured concentration is necessary 

in order to account for high or low fluid intake periods, periodic loss of 

water by perspiration, and general metabolic influences.



One fairly typical correction involves an assessment of the amount of 

creatinine in each urine sample.  Creatinine is a protein produced by muscle and 

released into the blood. The amount produced per day is relatively stable in a 

given person.  Adult males typically excrete it at a rate of about 1.7 grams per 

day, and the excretion rate for adult women is about 1.0 grams per day.  

However, age and body weight, as well as sex, influence the excretion rate as well.



A simple ratio of the "expected" creatinine content to that which is measured 

in the urine sample provides a means of converting the amount of 

radioactivity (if any) in the sample to the equivalent amount of radioactivity that would 

have been present if a true 24-hour collection of urine was submitted.



I hope this helps. Have a good weekend!



Carol D. Berger

Integrated Environmental Management, Inc.

8 Brookes Avenue, Suite 205

Gaithersburg, Maryland 20877

(240) 631-8990

CDBerger@IEM-Inc.com



Please visit our web site at http://www.IEM-Inc.com

************************************************************************

You are currently subscribed to the Radsafe mailing list. To unsubscribe,

send an e-mail to Majordomo@list.vanderbilt.edu  Put the text "unsubscribe

radsafe" (no quote marks) in the body of the e-mail, with no subject line.

You can view the Radsafe archives at http://www.vanderbilt.edu/radsafe/