Nurses review, evaluate, and use diagnostic test results on a routine basis. However, the skills necessary to evaluate a particular test using statistical outcome measures is often lacking. The purpose of this article is to examine and interpret the underlying principles for use of the statistical outcomes of diagnostic screening tests (sensitivity, specificity, and positive (PPV) and negative (NPV) predictive values, with a discussion about use of SpPIn [Specificity, Positive test = rule in], and SnNOut [Sensitivity, Negative test = rule out]) in advanced nursing clinical practice. The authors focus on NPVs because test results with high NPV are useful to practitioners when considering unnecessary, costly, and possibly risky treatments, whether using clinical assessment tool, test, or procedure or using polymerase chain reaction analysis of DNA test results. In this article, the authors emphasize the use of NPV in treatment decisions by providing examples from critical care, neonatal, and advanced forensic nursing, which become a framework for assessing decisions in the clinical arena. This commentary stresses the importance of the NPV of tests in preventing, detecting, and ruling out disease, where PPV may not be relevant for that purpose. Negative predictive value percentages inform treatment decisions when the provider understands the biology, chemistry, and foundation for testing methods used in clinical practices. The art of diagnosis, confirmed in a test’s high NPV (meaning the patient probably does not have the disease when the test is negative), reassures provider treatment stewardship to do no harm.
Reba A. Umberger, PhD, RN, CCRN-K, is an assistant professor at the College of Nursing, The University of Tennessee, Knoxville. Dr Umberger’s program of research is focused on immune suppression in patients with sepsis (including genetic, epigenetic, and environmental risk factors for subsequent infection) and long term outcomes in survivors of sepsis and their informal caregivers.
Linda A. Hatfield, PhD, NNP-BC, is an assistant professor of evidence-based practice at the School of Nursing, University of Pennsylvania; and director of Research and Evidence-Based Practice, Department of Nursing, Pennsylvania Hospital, Philadelphia. Dr Hatfield’s program of funded research investigates the analgesic properties of behavioral and environmental interventions, the genetic association between treatment interventions and infant pain physiology, and the long-term effects of undermanaged pain in infants and young children.
Patricia M. Speck, DNSc, APN, FNP-BC, DF-IAFN, FAAFS, FAAN, is a professor, faculty in PhD, DNP, and MSN programs, and Coordinator of Advanced Forensic Nursing program of study at the School of Nursing, The University of Alabama at Birmingham. Dr Speck’s current funded program of research includes DNA detection, factors influencing DNA recovery, and injury. Her program of research is informed by over 30 years of clinical practice, policy development, and systems evaluation on behalf of patients experiencing an intersection with the legal system.
The authors have disclosed that they have no significant relationship with, or financial interest in, any commercial companies pertaining to this article.
Address correspondence and reprint requests to: Reba A. Umberger, PhD, RN, CCRN-K, College of Nursing, The University of Tennessee, 1200 Volunteer Blvd, Room 345, Knoxville, TN 37996 (firstname.lastname@example.org).