What is the difference between crcl and gfr

Many methods for assessing kidney function have been developed over the past century, most notably measurements of serum creatinine, glomerular filtration rate GFR , urea, and cystatin C.

However, all techniques for measuring GFR are time-consuming and tedious. Measurement of serum creatinine and cystatin C are more convenient and rapid tests for evaluating kidney function. Especially for within-individual monitoring, both are reliable kidney function tests for detecting both acute and chronic declines of kidney function [3].

Plotted from data in J Am Soc Nephrol ; Note also that the reference ranges for serum creatinine approximately 0. While both serum creatinine, cystatin C, eGFRs, and mGFRs by creatinine, inulin, iothalamate all have relatively large and proportionately similar reference ranges [8,9], the within-individual variations for serum creatinine, cystatin C, and eGFR are much lower than for mGFR by creatinine clearance [5,10], or by iothalamate and inulin methods [7,11].

As expected, eGFRs calculated from creatinine or cystatin C correlate poorly with clearance measurements of GFR, either by creatinine, iothalamate or inulin clearance, especially in the normal range [5,9,11].

Creatinine methods are now commonly standardized to an isotope-dilution mass spectrometry IDMS reference method [12], which should lessen the systematic bias between methods and improve agreement among both creatinine and eGFR results from different institutions. However, it will have no effect on either the imprecision of a particular creatinine method or on the inherent random differences between calculated eGFR and measured GFR.

Plasma concentrations of cystatin C are reliable markers for detecting and monitoring the progression of kidney disease. Both creatinine and cystatin C are each affected by factors other than GFR, with creatinine affected by factors related to muscle mass age, gender, and race , and cystatin C affected by age, inflammation, obesity, and diabetes [13].

Like serum creatinine, cystatin C concentrations were much more stable in individuals without renal disease than was GFR measured by creatinine clearance [5]. A possible advantage of cystatin C with minor glomerular damage is that, being a large molecule, blood levels of cystatin C might rise sooner than creatinine. Several reports also indicate that cystatin C is better than creatinine for predicting risk in cardiovascular disease [14], although other studies did not conclude that cystatin C improved risk prediction [8,15].

Cystatin C is also a more costly, slower, and less available test than creatinine. Cystatin C now has a certified reference material available that should improve method standardization for that analyte. Am J Kidney Dis It was based on normalizing serum creatinine for age, gender, and race, with factors included to numerically resemble GFR [21].

The intent was to provide a kidney function parameter that would lessen the likelihood of chronic kidney disease CKD going unnoticed by non kidney specialists. Furthermore, nephrologists commonly find the eGFR to be 2 in elderly persons with no evidence of kidney disease and who have a serum creatinine that is stable at a slightly elevated level. As such, the eGFR should be interpreted as an independent parameter for detecting and monitoring kidney function.

If both eGFR creat and eGFR cysC are available, a discrepancy between the two could indicate the need for further testing, such as with iohexol clearance [22]. In each case, the discrepancy was due to technical problems with the iohexol procedure [23]. May contain information that is not supported by performance and intended use claims of Radiometer's products.

See also Legal info. Radiometer and acutecaretesting. Printed from acutecaretesting. June Clarifying the confusion of GFRs, creatinine, and cystatin C.

The advantages of serum creatinine and cystatin C, and eGFR will be discussed. Because of the difficulties of measuring GFR, equations have been developed to calculate an estimated GFR eGFR from serum creatinine and cystatin C and demographic factors such as age, gender, race, and weight. Misconceptions about all these kidney function tests are common, including serum creatinine, mGFR by clearance tests creatinine, iothalamate, inulin, etc.

If the percentage of creatinine that is secreted is ignored, then all of the filtered creatinine equal to the product of the GFR and the serum creatinine concentration [SCr] will be excreted equal to product of the urine creatinine concentration [UCr] and the urine flow rate or volume [V]. This formula is called the creatinine clearance and tends to exceed the true GFR by 10 to 20 percent or more depending upon the proportion of urinary creatinine that is derived from tubular secretion.

For more, see this article. However, clinical biochemistry laboratories provide CKD-EPI glomerular filtration rate estimations, resulting in discrepancies between clinical trial and routine use of the drugs.

Keywords: Atrial fibrillation; Chronic kidney disease; Creatinine clearance; Glomerular filtration rate; Oral anticoagulation. Figure 1: Function of a Nephron. The normal GFR value varies with age, sex, and body size. But, GFR between these values within more than three months along with another symptom like persisting protein in the urine indicates early kidney disease. More importantly, the GFR measurement is important for the diagnosis, prognosis, and treatment of kidney disease.

CrCl creatinine clearance rate is the amount of creatinine cleared out from the blood due to the renal function. Serum creatinine is a waste product produced due to muscle movements.