Creatinine Standardization Is Here: What Does It Mean for Labs

As IVD manufacturers work behind the scenes to meet the new creatinine assay standardization guidelines, laboratories are gearing up for a change in their processes. Whether these changes will be extensive or minor will vary from lab to lab, but one thing is for sure: the standardization will allow physicians to provide better care to patients with Chronic Kidney Disease (CKD).

Recap of the Recommendations
The recommendations by the National Kidney Disease Education Program’s (NKDEP’s) Laboratory Working Group call on laboratories to:

• Use a creatinine method that is traceable to the internationally accepted reference method: Isotope Dilution Mass Spectrometry (IDMS).
  
• Report estimated Glomerular Filtration Rate (eGFR) together with serum creatinine results. (Together the two are the best indices of kidney function.) 
• Use the standard MDRD equation (from the Modification of Diet in Renal Disease study) when estimating GFR. This equation factors in creatinine level, age, gender and race to determine eGFR.

These recommendations not only impact IVD manufacturers and clinical laboratories, but also pharmacists, proficiency-testing provider organizations and LIS vendors.

By tackling this issue, all the stakeholders are joining together in the name of better patient care. A more standardized approach to testing will help physicians better identify and treat CKD, a condition that affects 10 to 20 million people in the United States alone.

Assay Changes Ahead
The NKDEP recommended the MDRD equation as the preferred method for estimating GFR, but in fact there are two different MDRD equations:

• the “conventional calibration MDRD equation”
  
• and the “IDMS MDRD equation” for use with assays that are traceable to isotope dilution mass spectrometry (IDMS).

Of these, the IDMS-traceable method is preferred because it is the international reference method, providing common harmonization of creatinine results.

The bottom line: labs need to transfer to this method if they are not already using it. For labs using a different method, this could mean a great deal of change, requiring much communication with physicians, pharmacists and other stakeholders.

“The good news is that this standardization is receiving wide acceptance from urologists and nephrologists,” says James D. Peele, Ph.D., director of clinical chemistry at Baptist Medical Center in Jacksonville, Florida (USA). “They recognize the need and they can be advocates for the laboratory, helping to communicate with other physicians and healthcare providers.”

Next Steps
Laboratories using Beckman Coulter’s creatinine reagents and calibrators will be receiving software and instruction letters over the next few months to guide them through the transition to IDMS-traceable creatinine results.

“Our mission is to make the transition as easy as possible,” says Jack Zakowski, Ph.D., director of scientific affairs for Beckman Coulter’s chemistry systems.

Ultimately, the standardization will yield long-term benefits for laboratories, physicians and patients. “We’ll have uniform results that can be compared more easily,” says Dr. Peele. “And most important, patients will receive the best care possible.”

For more information, visit the NKDEP website at www.nkdep.nih.gov.

Creatinine Calendar

• January 2006
  The NKDEP announces its recommendations for standardizing creatinine testing.

• June 2006
  Beckman Coulter participates in a Commutability Study with six other manufacturers to assign creatinine value to reference material.

• February 2007
  NIST Reference Material is available to all IVD manufacturers, giving them the information they need to begin reformulating assays.

• April 2007
  Detailed communication is sent to Beckman Coulter customers.

• Third Quarter 2007
  Upgrade Kit will be released to customers.