Normal hematocrits in preadolescent children

Area of Science:

• Pediatrics
• Hematology
• Clinical Chemistry

Background:

• Establishing accurate reference ranges for hematocrit is crucial for diagnosing anemia and other hematological conditions in children.
• Previous studies may not reflect current population norms or account for variations in measurement techniques.
• Adolescent hematological values can differ from adult values and may show sex-specific trends.

Purpose of the Study:

• To determine the normal range of hematocrit values in healthy children aged 11, 12, and 13 years.
• To compare hematocrit levels between boys and girls in this age group.
• To assess the validity of using this population as a source for normal hematocrit values.

Main Methods:

• A cohort of 471 children from an affluent Pittsburgh suburb were studied.
• Microhematocrit readings were standardized to Wintrobe hematocrit tube values.
• Hematocrit distributions were analyzed for normality and central tendency.

Main Results:

• A true Gaussian distribution was observed, supporting the use of these children as a "normal" reference group.
• The mean hematocrit was 43%, with 95% confidence intervals of 39% to 47%, consistent for both boys and girls.
• These values are higher than commonly accepted normal ranges, particularly for girls, whose values approached those of adult women.

Conclusions:

• The established hematocrit values represent a valid "normal" range for healthy adolescents aged 11-13.
• Adolescent girls' normal hematocrit levels are comparable to adult women.
• A separate analysis of 220 black children indicated a skewed distribution, suggesting a higher prevalence of anemia in this subgroup.