Schwartz equation

Description[edit | edit source]

Formula for estimating clearance creatinine in children using:

serum creatinine – Cr_serum [mg/100ml];
height of the patient – H [cm];
proportional constants – for age and gender groups [3.46*10^-8kg*s^-1*m^-2].

$CCr_{Schwartz}={\frac {k*H}{Cr_{serum}}}$

Schwartz constant
group	constant	constant for calculation with μmol/l
Infant or newborn with low birth weight (<1 year)	0.33	29
Newborn (<1 year)	0.45	39
Child or adolescent girl	0.55	49
Adolescent boy	0.70	62

Coefficients for other input units[edit | edit source]

Some laboratories, for example the one in FN Motol, give serum creatinine in μmol/l, it is then more practical to use adjusted constants for calculation.

Note[edit | edit source]

The formula becomes inaccurate at higher clearance values, so if the CCr rises above 75 mL/min per 1.73 m2, the results should not be considered accurate.

Indicative assessment of GFR in children[edit | edit source]

The value derived from the Schwartz formula indicates the maximum level of plasma creatinine in a child of a given body height:

P_{kr (max. in μmol/l)} = v_cm * 0.54

in_cm... child's height in centimeters

The index already calculates with a lower limit of GFR of 90 ml/min/1.73 m² = 1.5 ml/s/1.73 m². The formula is indicative, in the case of repeated pathological findings, it requires control by classical methods.