Age- and sex-specific reference intervals for complete blood count parameters in capillary blood for Chinese neonates and infants: A prospective study.

Background: The reference intervals (RIs) of laboratory tests are essential for disease diagnosis, therapy monitoring, and health assessment. They are also significant for clinicians to discriminate between subjects with disease and healthy subjects. However, RIs for complete blood count (CBC) parameters in capillary blood for children are deficient. This study aimed to establish capillary blood RIs for blood cell parameters in neonates and infants from birth to 2 years of age in Zhengzhou.

Methods: We prospectively collected a total of 1840 capillary blood specimens from healthy subjects from birth to 2 years of age. Hematology RIs were established by analyzing capillary blood sample data, and RIs and 90 % confidence intervals (CIs) were calculated according to Clinical and Laboratory Standards Institute (CLSI) C28-A3 guidelines.

Results: RIs were established for hematological parameters of capillary blood in neonates and infants from birth to 2 years of age. The levels of almost all hematological parameters, except for the lymphocyte (LYMPH), platelet (PLT), and thrombocytocrit (PCT) parameters, peaked in the first month after birth and then decreased to lower levels within 6 months. There were significant sex differences in most erythrocyte-related parameters, with higher levels in males than in females. Erythrocyte-related parameters showed an increasing tendency with increasing age after the second month. Neutrophil (NEUT) levels were high on the third day of life, declined to a nadir in the first month, and then slowly increased with age. LYMPH levels were low at birth and began to increase after birth, peaked at approximately-six months of age and then gradually declined with age. PLT and PCT levels showed an increasing trend during the first month, while the other parameters showed a decreasing trend. All platelet-related and leukocyte-related parameters showed no significant difference with sex.

Conclusion: We provide comprehensive age- and sex-specific RIs, including RIs for neonates in Henan. Our study provides more comprehensive reference ranges for Child Health Hospital and children's medical institutions, which may facilitate preliminary screening, diagnosis, and therapy.