Describe the relationship between creatinine clearance and serum creatinine concentrations. What are the potential pitfalls in using serum creatinine concentrations to assess renal function in a critically ill patient in ICU?
It was expected candidates would describe that both these are surrogate measures for
Glomerular filtration rate. Credit was given for clear definitions, formula and normal values
(such as plasma clearance is the volume of plasma cleared per unit time). It was expected
candidates could explain that serum creatinine results from a balance of creatinine produced
and excreted and hence the slow response time and limitations for its use because of changes
in both production and excretion.
Extra credit was given for appreciating the non linear relationship between changes in serum
creatinine and creatinine clearance and that significant changes in glomerular filtration can
occur before this is reflected in the serum creatinine. Comment on the problems of dilution
with acute changes in fluid balance and that tubular secretion of creatinine can occur when
the serum creatinine concentration is high both gained extra marks.
Syllabus D1 2
Reference Ganong 22nd edition 699-728
Shemesh, Ovadia, et al. "Limitations of creatinine as a filtration marker in glomerulopathic patients." Kidney Int 28.5 (1985): 830-838
Delanaye, Pierre, Etienne Cavalier, and Hans Pottel. "Serum creatinine: not so simple!." Nephron 136.4 (2017): 302-308.
Perrone, Ronald D., Nicolaos E. Madias, and Andrew S. Levey. "Serum creatinine as an index of renal function: new insights into old concepts." Clinical chemistry 38.10 (1992): 1933-1953.
Bleiler, Roberta E., and Harold P. Schedl. "Creatinine excretion: variability and relationships to diet and body size." The Journal of laboratory and clinical medicine 59.6 (1962): 945-955.
Mayersohn, Michael, KENNETH A. Conrad, and R. A. M. A. N. U. J. Achari. "The influence of a cooked meat meal on creatinine plasma concentration and creatinine clearance." British journal of clinical pharmacology 15.2 (1983): 227-230.
Pottel, Hans, et al. "Establishing age/sex related serum creatinine reference intervals from hospital laboratory data based on different statistical methods." Clinica chimica acta 396.1-2 (2008): 49-55.
Bauer, John H., Charles S. Brooks, and Rebecca N. Burch. "Clinical appraisal of creatinine clearance as a measurement of glomerular filtration rate." American Journal of Kidney Diseases 2.3 (1982): 337-346.
Cockcroft, Donald W., and Henry Gault. "Prediction of creatinine clearance from serum creatinine." Nephron 16.1 (1976): 31-41.