December 2014 Vol. 2 No. 3

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Original Research Article

Reference limits of serum total and bone alkaline phosphatases in apparently healthy Sudanese children aged 5-16 years

Amira A.K. Humeida¹, Ihsan M. Osman², Enaam A. Abdelgadir¹, Sana E. Abdalla^3*, Alya A. Salman⁴
and Abdelhafiz H. Khattab⁵
 

¹Al Neelain University Faculty of Medicine Pathology Department
²Al Zaiem Alazhari University Faculty of Medicine Pathology Department
³Al Neelain University Faculty of Medicine Al Neelain Medical Research Centre
⁴Khartoum College of Medical Science.
⁵Khartoum University Faculty of Medicine Pathology Department

*Corresponding Author's E-mail: sanaseed@hotmail.com

Accepted December 15, 2014

Abstract

Alkaline phosphatase (ALP) activity is present in most organs of the body and is especially associated with membranes and cell surfaces located in the small intestines, bone osteoblasts, liver and placenta. Elevations in serum ALP activity commonly originate from the liver and bone. Consequently, serum ALP measurements are of particular interest in the investigation of hepatobiliary diseases and bone disease associated with increased osteoblastic activity such as in growing children due to rapid growth of bone. An elevated ALP almost always requires other tests to determine the origin of the enzyme. One of these tests is measurement of ALP isoenzymes using electrophoresis or immunoassays. The aim of this study is to estimate the reference limits of the total and bone ALP in growing children according to age and sex, and determine the age at which these enzymes reach their maximum peaks in both sexes as well as determining the percentage of bone ALP from total ALP according to age and sex. This study is a descriptive cross-sectional study done in Khartoum State in which 120 children aged 5-16 years from both sexes were included in this study. All children were weighed and height was determined for each child and compared with the growth charts for age and sex to ensure normal growth. Total ALP and bone isoenzyme were measured for each child then the normal limits were set according to age and sex. Total and bone ALP reference limits were recorded as the 5th and 95th percentiles for each age between 5-16 years and sex. Those levels were found to be higher than those obtained in other studies in other countries and that levels were higher in boys than girls. The peaked levels of total ALP and bone isoenzyme were found to be at the age of 14 and 13-14 years age group in boys and at the age of 10 and 9-10 years age group in girls. The percentage of bone isoenzyme from the total ALP was 76%-97% in boys and 71%-95% in girls. There was no relationship between the level of bone ALP and the height of children studied. Total ALP and bone isoenzyme have different levels at different ages and between sexes in growing children and by setting the normal limits, physiological and pathological elevations could be distinguished accordingly.

Keywords: Isoenzyme, Liver, Osteoblastic, Phosphatase