Table 1.

Estimative dietary equations and urinary measures of net endogenous noncarbonic acid production and its determinants (potential renal acid load and organic acids)

Equation	Formula
NEAPF, mEq/d	= (0.91 × protein in g/d) − (0.57 × potassium in mEq/d) + 21
NEAPR, mEq/d	= PRAL + OAanthro
NEAPL, mEq/d	= PRAL + OAdiet
NEAPS, mEq/d	= PRALS + OAdiet
PRAL, mEq/d	= ([0.488 × protein in g/d] + [0.0366 × phosphorus in mg/d]) − ([0.0205 × potassium in mg/d] + [0.0263 × magnesium in mg/d] + [0.0125 × calcium in mg/d])
PRALS, mEq/da	= ([0.75 × sulphate] + [0.63 × phosphorus]) − ([0.80 × potassium] + [0.25 × calcium] + [0.32 × magnesium]) (all in mEq/d)
OAanthro, mEq/d	= body surface area × 41 / 1.73
Body surface area, m2	= 0.007184 − height (cm)0.725 − weight (kg)0.425
OAdiet, mEq/d	= 32.9 + (0.15 × [{potassium} + {calcium × 2} + {magnesium × 2} – {phosphorus × 1.8}]) (all in mmol/d)
UPRAL, mEq/d	= ([sulphate × 2] + [phosphorus × 1.8]) − (potassium + [magnesium × 2] + [calcium ×2]) (all in mmol/d)
UNEAP, mEq/d	= UPRAL + total urine organic acid (both in mEq/d)
NAE, mEq/d	= titratable acid + ammonium − bicarbonate (all in mEq)

NAE, net acid excretion; NEAP_, net endogenous acid production estimated by dietary records where NEAP_R pertains to the equation by Remer and Manz,⁷ NEAP_F to the equation by Frassetto et al.,⁶ NEAP_L to a model attributed to Lemann,11, 12, 13 and NEAP_S to the equation by Sebastian et al.⁹; PRAL, potential renal acid load estimated by dietary intake where PRAL is the equation by Remer and Manz⁷ and PRAL_S pertains to the equation by Sebastian et al.⁹; _UNEAP, net endogenous acid production determined by urine analysis; _UPRAL, potential renal acid load determined by urine analysis; OA, organic acids where OA_anthro pertains to the anthropometric estimate by Manz et al.¹⁰ and OA_diet to the estimative equation by Kleinman and Lemann.¹¹

^aPrior to using PRAL_S, when converting mmol of phosphorus to mEq, 1.8 is used as the conversion factor.