Not Just Small Adults

For most of the 20th century, laboratory investigations for children were usually undertaken as part of a service for patients of all ages. There was limited appreciation of the differences between results for adults and those for children. What might be a concerningly high serum alkaline phosphatase activity for an adult, for instance, would have been a normal result for a growing child – but, without including age-related reference ranges, the report may not have conveyed this information. Some of the earliest books to describe pediatric reference intervals were published in the 1980s by Blackwell Scientific Publications and by the American Association for Clinical Chemistry – and, from then on, we have become increasingly aware of the many differences between younger and older populations. In fact, an experienced pathologist suggests that the greatest advances in pediatric biochemistry over the last 40 years have been in newborn screening and more accurate pediatric reference intervals (1).