Background. Ultrasound map detect mild splenomegaly before it is clini
cally palpable, Knowledge of the normal range of spleen size in the po
pulation being examined is a prerequisite. Racial differences in splen
ic length could result in incorrect interpretation of splenic measurem
ents. Objective. To measure the normal values of splenic length in Hon
g Kong Chinese children and compare the results with Western data: to
determine whether there is a constant ratio of the length of the splee
n to the left kidney, which could be used to diagnose splenomegaly, wi
thout reference to a nomogram. Materials and methods. Ultrasound was u
sed to measure maximum splenic and left kidney length in 256 Chinese c
hildren to obtain normal values for spleen length and to determine the
spleen/kidney ratio. Results. Splenic length in Chinese children is s
imilar to Western children up to the age of about 15 years, The spleen
/left kidney ratio is strikingly constant with a mean value of 1, Usin
g 2 SD above the mean as a guide, the upper limit of normal for the sp
leen/kidney ratio is 1.25. Conclusion. Splenomegaly should be suspecte
d in children if the spleen is more than 1.25 times longer than the ad
jacent kidney.