Improving The Management Of Patients With Chronic Kidney Disease - Roche Enzymatic Creatinine Assay For Specific And Reliable Results

Main Category: Urology / Nephrology
Article Date: 26 Jun 2009 - 3:00 PDT

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The Roche Creatinine Plus enzymatic creatinine assay, for use with cobas® or MODULAR Analytics analysers, offers a specific and accurate alternative to the less specific Jaffé method, ensuring clinically more reliable results in the management of patients with chronic kidney disease (CKD)1. Users at GSTS (Guys, St Thomas', Serco) Pathology, London and the University Hospital, Coventry, amongst others, have found that the assay provides a more accurate assessment of renal function.

Supporting a large renal unit, the Biochemistry Department at GSTS Pathology, London performs over 30,000 creatinine tests every month. They have been using the enzymatic Roche Creatinine Plus assay first line for the last three years. "We found the enzymatic test to be more reliable and less prone to interference," explains senior biomedical scientist, Kim Brown. "This has resulted in a reduction in discrepant results, which means that fewer patients are required to be re-bled. Accuracy is extremely important in monitoring pre- and post-transplant patients, since consultants may need to act on a slight change in eGFR. The more accurate Creatinine Plus assay ensures that fewer patients are required to undergo unnecessary invasive procedures."

Similarly, Dr Steve Smith, Service Director of the Clinical Biochemistry and Immunology Department in Coventry has been using the Roche Creatinine Plus assay first line for the last 2 years. Performing around 36,000 creatinine tests every month, he prefers to use a more specific IDMS standardized method. "The Creatinine plus assay enabled us to use the newer MDRD eGFR equation directly since this was generated using the Roche enzymatic assay," comments Dr Smith. "Creatinine Plus is easier to handle on our Roche MODULAR platform than our previous method. Also, being more specific, we get a more accurate picture of a patient's creatinine level, particularly at lower levels where non creatinine chromogens interfere disproportionately with the older Jaffé assay. This is particularly important since we receive a large number of samples from both paediatric and renal patients, for whom there can be significant interference using Jaffé methods."

By providing more accurate results, the Roche Creatinine Plus assay helps to improve patient care and offers a cost effective alternative to less specific methods.

With 183 different assays, Roche offers the largest menu of tests available on an automated SWA (serum work area) platform. For further information about this extensive range and for details of current offers relating to the affordable Roche Creatinine Plus assay, telephone the Roche Centralised Diagnostics team on 01444 256750 or visit http://www.roche-diagnostics.co.uk

References

1. Junge, W., Wilke, B., Halabi, A. and Klein, G. (2001) Creatinine excretion and creatinine clearance: determination of reference intervals using a specific enzymatic and a modified Jaffé method. EUROMEDLAB, Praha 2001, 26-31 May 2001, Prague.

2. Cobbaert, C.M., Baadenhuijsen, H. and Weykamp, C.W. (2009) Prime time for enzymatic creatinine methods in paediatrics. Clin Chem 55:549-558

3. Panleghini, M. (2008) Enzymatic assays for creatinine: Time for action. Scan J Clin & Lab Invest. 68 S241: 84-88.

Hospitals are finding that the Roche Roche Creatinine Plus enzymatic creatinine assay provides a more accurate assessment of renal function than the less specific Jaffé method

Background to Creatinine

Creatinine levels in serum or plasma are used to calculate the estimated glomerular filtration rate (eGFR), using the recommended MDRD formula, in order to identify and monitor patients with stage 3 - 5 CKD, as required by the Department of Health Quality and Outcomes Framework (QOF).

The Jaffé method is used to determine levels of creatinine in serum or plasma. It is based on the reaction of creatinine with alkaline picrate, resulting in the formation of a yellow/red complex. Serum and plasma samples contain proteins which react non-specifically in the Jaffé method. In order to obtain accurate values the serum and plasma results are then corrected by a specified value.

Certain substances found in blood, such as albumin, immunoglobulin G and foetal haemoglobin, commonly interfere with Jaffé creatinine assays, resulting in inaccuracies in the calculation of eGFR2,3. Such inaccuracies can be significant when monitoring patients with CKD, particularly in children and neonates, since even small changes in eGFR may affect clinical decisions. The more specific enzymatic method, on the other hand, is not affected by such interference, providing more reliable estimates of GFR2,3.

Source
Roche