Serum Alkaline Phosphatase Levels in Healthy Children and Evaluation of Alkaline Phosphatase z-scores in Different Types of Rickets

Abstract

Objective: Serum alkaline phosphatase (ALP) levels show great variation with age and sex in children and adolescents. Additionally, different buffers used even in the same method cause variable results. This detail is not usually taken into account in the evaluation. We aimed to study pediatric age- and sex-specific reference ranges for ALP by colorimetric assay using p-nitrophenyl phosphate as substrate and diethanolamine as buffer and also to compare the ALP levels in patients with different types of rickets. Methods: 1741 healthy children and adolescents (904 girls) were included in the study for normative data. 77 different ALP measurements from 38 nutritional rickets (NR), 7 vitamin D-dependent rickets (VDDR) and 8 hypophosphatemic rickets (HR) patients were included. Results: Reference values for ALP were constructed. ALP levels demonstrated a tetraphasic course with two peaks at infancy and puberty. There was no difference in ALP levels between boys and girls until puberty. However, higher ALP levels were noted at 10-11 years in girls (p=0.02) and at 12-13, 14-15, 16-17 years in boys (p<0.001). ALP levels start to decline after age 12 and 14 in girls and boys, respectively. Serum ALP levels were highest in the VDDR group and lowest in the HR group (median z-score values in HR, VDDR and NR were 3.6, 10.4 and 6.5, respectively; p<0.001). Similarly, plasma parathormone(PTH) levels ranged from highest to lowest in the VDDR, NR and HR groups (median values: 525, 237 and 98 pg/mL, respectively; p<0.001). Conclusions: This normative data will provide a basis for better evaluation of ALP levels determined by the described method. Furthermore, use of z-scores gives a more precise assessment of changes in ALP levels in rickets and other bone disorders. Conflict of interest:None declared.

Studying the Enzymes Levels in Cerebrospinal Fluid for Children With Acute Lymphoblastic Leukemia

“…The results in tables (4) and (5)shows a significant increase (P<0.05) in ALP activity in CSF of leukemia patients for both sexes and all age group compared with the control group and the enzyme activity was in male higher than female and its proportional with age and this was in agreement with Turan et al [37] Several studies reported elevation of ALP activity in early stages of patients serum of ovarian cancer, breast cancer, prostate cancer, brain cancer, esophageal cancer, colorectal cancer and lung cancer when compared with normal controls [38] viral hepatitis, liver cirrhosis [24] acute lymphoblastic leukemia [39] the elevation in ALP activity occurs because of the accelerated denovo synthesis of the enzyme [40] or because the increase of tumor necrosis factor-α and its direct effect on the expression of alkaline phosphatase in vascular smooth muscle cells as well as how ALP affects the inflammatory responses and may play a direct role in preventing organ damage. [41] www.wjpps.com …”

Participation of sex hormones in multifactorial pathogenesis of adolescent idiopathic scoliosis

“…8 Mean concentration of RANKL in the groups of girls studied for bone formation to assess osteoblastic activity. Both markers are increased in metabolic bone diseases with increased bone or osteoid formation including osteopenia, osteoporosis, as well as in adolescent idiopathic scoliosis [39][40][41][42][43][44].…”

Pediatric reference intervals for alkaline phosphatase

“…Alkaline phosphatase is a ubiquitous enzyme in humans and an important biomarker for skeletal and hepatobiliary diseases [1][2][3]. Clinical interpretation is enabled with reference intervals, which allow classification of samples in the context of intra-and inter-individual variation.…”