What do studies say about Blutbild Kinder?

The provided context does not contain studies on pediatric blood count ('Blutbild Kinder'). The contexts cover population genetics (rs182549, lactase persistence), pharmacogenetics (CYP2C19*2), and general critique of direct-to-consumer genetic testing. None of these address pediatric blood count parameters or their reference ranges. Studies on children's blood counts are well-established in clinical pediatrics and hematology (e.g., age-dependent normal values for hemoglobin, leukocytes, platelets). The evidence comes from large cohort studies and guidelines, not from the genetic data provided. Therefore, no meaningful answer can be given based on the given context.