Abstract

Background: Transient hyperphosphatasemia of infancy and early childhood (THI) is characterized by a temporary, isolated elevation of serum alkaline phosphatase (ALP) in the absence of hepatic or skeletal pathology. ALP levels may exceed the upper limit of the age-specific reference range by several-fold, while other biochemical and clinical parameters remain normal. Recognition of THI is crucial to avoid unnecessary investigations.
Methods: Two pediatric cases with markedly elevated ALP were evaluated through laboratory tests, imaging, and clinical follow-up to exclude hepatic or metabolic bone diseases.
Results: Both cases demonstrated spontaneous normalization of ALP within 2 - 3 months, confirming THI.
Conclusions: THI is a benign, self-limiting condition requiring no intervention. Increased awareness among clinicians is essential to prevent overdiagnosis and parental anxiety.

DOI: 10.7754/Clin.Lab.2025.250351