Jelliffe equation

Several equations have been developed to assess unstable kidney function. The Jelliffe equation (Table 22-1) estimates creatinine clearance by considering the change in serum creatinine over a specified time period.11 While it is more mathematically difficult to calculate, it better estimates creatinine clearance in patients with rapidly changing kidney function compared to an equation that only includes a single creatinine concentration. 

Serum creatinine values can fluctuate widely in patients with unstable renal function. Although some practitioners advocate use of the Cockcroft-Gault equation using the highest of the two serum creatinine values, most recommend calculation of CLcr using either the Brater or Jelliffe equations. 

GFR in this patient population. Huang and associates reported the inability of several CLc, equations to predictrenal function in hospitalized patients with advanced human immunodeficiency virus disease. All methods, including CG, Jelliffe, and Mawer, overestimated the measured 24-hour CLc,. The reasons for the poor predictability of these methods is unclear, although 24-hour collection methods often yield highly variable results because of inadequate urine collection. 

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