This textbook helps nurses, physician assistants, medical students and residents to order appropriate tests and understand how to interpret them to improve their diagnostic reasoning. Children are not like adults, and interpreting of the results of their diagnostic laboratory tests requires knowledge of the biochemical and metabolic differences. Using a combination of information, questions and case studies, the book allows readers to gain an understanding of the key concepts of sensitivity, specificity, and positive and negative predictive values, as well as the indications for diagnostic lab tests. This textbook presents the state of art in testing across body systems and guidance on how to order and interpret diagnostic laboratory tests in pediatric patients. Each chapter includes learning objectives, tables and figures, as well as questions and references for further learning. This textbook provides an update for clinicians and is a valuable learning tool for students and new clinicians.

Rita Marie John, EdD, DNP, CPNP, PMHS, FAANP, is Special lecturer at Columbia University. Since 1980, she worked with underserved populations working in Newark and Plainfield, N. J., for most of her 40-year career as an NP. She has worked in primary care and emergency medicine. Dr. John joined the faculty of Columbia in 1997 and was the PNP program director until September 2018. She has also mentored DNP students. Her research interest centers on informatics, nursing education, and primary care issues, including immunizations, diagnostic labs, and obesity. Her past awards include the Seton Hall University Hall of Honor; Dorothy H. and Thomas L. ONeil Distinguished Faculty Award for teaching; membership in the Anna Maxwell Teaching Academy, Columbia University; and writer of the year 2019 for The Nurse Practitioner. Dr. John is a fellow of the American Academy of Nurse Practitioners. Dr. John has presented multiple times for local, regional, national, and international venues. She has presented for the National Conference given by NAPNAP on diagnostic labs more than six times. Dr. John has also presented on diagnostic labs for NAPNAP at two regional symposiums, as well as presenting for both state and local NAPNAP associations. While at Columbia, she developed Pedialabs: A Case-based Approach. Pedialabs is an online case approach to the Complete Blood Count. There were 20 cases developed for students to interpret hematology labs and enhance decision-making on follow-up.Dr. John also is the author of greater than 65 peer-reviewed articles and 27 book chapters. Dr. John currently reviews manuscripts for the following journals, including Journal for Nurse Practitioner, Journal of Pediatric and Adolescent Psychiatric Nursing, Journal of Pediatric Healthcare, Journal of Pediatrics, Journal of Pediatric Nursing, and the Journal of Doctoral Nursing Practice