Enzymatic creatinine assay and chemotherapy

Ian

Perhaps the following will help

To me what is most important is knowing the reference method the creatinine method is aligned with.

The largest issue is knowing if both or either are using calibrator values that are traceable to IDMS/MS

Most clearance equations were validated with non idms traceable creatinine. This means that if a IDMS creatinine is introduced doing calculations will be impacted

This is true regardless if Jaffe or enzymatic

For enzymatic the idea of 'no interference' is of course not true. There are far fewer cases however.

The US web site NKDEP has helpful information and guidance on back calculations

Best wishes and happy new year

Joe I

From: Clinical biochemistry discussion list <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Sent: Thu Dec 31 06:02:19 2009
Subject: Enzymatic creatinine assay and chemotherapy

We are changing our creatinine assay from a Jaffe based method to an enzymatic assay in the New Year.

We have had a query from our Pharmacy about the use of the Cockcroft Gault formula for calculating chemotherapy dosage with creatinine measured by the new assay.

What do other laboratories, who also measure creatinine with an enzymatic method, recommend?

Ian Holbrook
Department of Clinical Biochemistry
York Hospital
Wigginton Road
York
YO31 8HE
01904 725786