Health Information Management

Q&A: Guidelines for GFR calculations

CDI Strategies, May 23, 2013

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Q: Our lab does not calculate the Glomerular filtration rate(GFR) for patients over the age of 70. If I ask the physician to stage the chronic kidney disease (CKD), they ask me to calculate the GFR for them. If there a standard formula that should be used for this age group?

A:  It could be a high risk practice for CDI specialists to calculate the GFR for the provider. The GFR is not a calculation that is routinely done by the nursing staff, but even if it was, a CDI specialist, regardless of whether he or she has a nursing background, is not technically a part of the treating medical team. As such, it can appear leading or improper for the CDI specialist to calculate the GFR if it is not already provided within the lab values or within the health record.
Additionally, most guidelines discourage querying based on one abnormal lab value. One abnormal lab value often does not meet the definition of a secondary diagnosis as there must be additional monitoring, evaluation, or treatment (or increased nursing care or length of stay) based on that abnormal lab value to support a secondary diagnosis.
The GFR is not necessary for the diagnosis of CKD as a provider can use whatever method they deem appropriate for diagnosis and staging CKD; however, GFR is one of the most widely accepted tools for making that determination.  Most providers should have the resources to make such a calculation and then to use this information to determine the CKD stage.
That said, I support the tool on the National Kidney Foundation site as they are a credible organization whose findings are used to support the diagnoses of CKD and acute renal failure. Here is a link to their calculator:
Editor’s Note: Cheryl Ericson, MS, RN, CCDS, CDIP, AHIMA Approved ICD-10-CM/PCS Trainer, CDI Education Director for HCPro Inc., answered this question. Contact her at For information regarding CDI Boot Camps offered by HCPro visit

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