Laboratory tests are an integral part in the diagnosis of diseases in the pediatric age group and are commonly an essential part of the diagnostic workup and are important for selecting the most appropriate treatment.

Many new techniques and laboratory studies have been introduced in the last few years, and many have replaced older methods that have become obsolete. It has become essential to the practice of modern pediatrics to be familiar with advances in laboratory medicine, and it has become important to meet the demands of the practicing physician. As before the complexity and sophistication of many tests exceed the capabilities of many office or small hospital facilities; however, when necessary, these tests can be referred to specialized reference laboratories. These laboratories or facilities we have indicated and brought up-to-date in this edition.

We have, as in the previous edition, attempted to assemble this text into categories of disease with a brief outline of signs and symptoms that remain integral and essential for diagnosis. This is followed by diagnostic tests, including the most important methods for diagnosis with updates in molecular procedures, DNA, probes, monoclonal antibodies, polymerase chain reaction, immunocytochemical and cytochemical staining, flow cytometry, and cytogenetics.

Additional tables and algorithms have been included to add simplification, clarify, and to expedite the understanding and selection of diagnostic tests. Pertinent recent references are included and hematological disorders are illustrated.

The visual recognition, of parasites, urinary crystals, and blood cells, drawings and/or pictures are included.

As beforewe have used the conventional units for measurements and biochemical levels and have omitted the Système International (SI) units, because the latter is now rarely used, and the consensus amongst physicians is to maintain the use of conventional units.

In the 2nd edition we have updated the data and added much more to the infectious disease chapter particularly when new diseases have been identified. In addition the coagulation chapter has been rewritten and newmore recent references added. Updates throughout the book are included.

It is our hope that Clinical Use of Pediatric Diagnostic Tests will become essential for the needs of pediatricians, family practitioners, students, residents, pathologists, nurses, general practitioners, and laboratory technicians. We trust that our combined expertise in clinical pathology (laboratory medicine) and pediatrics, combined with out many years of teaching, has enabled us to meet these goals.

Enid Gilbert-Barness, M.D.

Lewis A. Barness, M.D.