Thanks to everyone who replied to my query.

 

I received the following responses……

 

1) We do the same as you but no evidence.

 

2) For amino acids we use 1.0 mmol/L. No evidence for validity of this value.

 

3) We use 1 mmol/L but again no evidence just a nice round number that few samples fall below.

 

4) We also choose <2.0. ? sensitivity of the Beckman urine creatinine method.

 

One well know NEQAS organiser (yes, the Scottish one) sent me some data to show that between lab agreement for creatinine

is quite good down to 1mmol/L. However as the average man excretes about 10mmol creatinine per day this would equate to a

urine output would of10L. So the question is perhaps not what is analytically valid but is the sample representative? It seems  

reasonable to suggest repeating the test on an EMU sample if the creatinine is less than about 2mmol/L.

 

Hello everyone,

 

A question related to samples for ACR, PCR or anything else reported as a ratio with creatinine…………...

 

When is a sample too dilute to produce a valid result?

 

We have traditionally flagged samples from adults with creatinine <2.0mmol/L as dilute and suggested

repeating on an EMU, but I’ve no evidence that 2.0mmol/L is a valid cut off.

 

What do the rest of you do with dilute samples and do you have you any evidence for your approach?

 

(If I receive replies directly I’ll anonymise them and post a summary later in the week).

 

Thanks,

 

Wayne.

 

Mr WH Bradbury

Consultant Biochemist

Biochemistry Department

Cumberland Infirmary

CARLISLE

Cumbria

CA2 7HY

Tel:     01228 814521

Fax:    01228 814831

E-mail: [log in to unmask]