Earn up to 14.5
Laboratory, Endocrine, & Neurotransmitter Symposium
October 4 - 6, 2019
Approved for 4.25 Pharm CEs from the OBNM!
Gain additional clinical insight and treatment considerations to evaluate some of the most prevalent and challenging conditions that patients present with, including depression, anxiety, altered mental focus and stamina, sexual dysfunction, sleep disturbances, addictions and dependencies, weight management, and chronic disease. Register now to get the early bird price of $329 (reg. $379).
Topic: Comprehensive Hormone Health for Men
By: Ruth Hobson, ND
July 3, 2019
Join Labrix clinical staff and special guests on the first Wednesday of every month at 9:30 AM and 12:00 PM PST. This free, live webinar series will cover a variety of neuroendocrine topics that will enhance your knowledge, with clinically applicable testing and treatment considerations. 1 CE credit available upon attendee request.
July 18 - 23, 2019
Labrix and Doctors Data will be in Denver for IFM (APM) on July 18-23. Don't miss our lunch presentation on hormones by Brandon Lundell, DC on July 18.
July 26-28, 2019
Make sure to visit our booth at IWHIM in Portland. Dr. Lylen Ferris from Labrix will be discussing neurotransmitters and the HPA axis on Friday, July 26. Chat with our booth representatives to learn what's new.
Sensitivity and Specificity
By Jack A. Maggiore, PhD, MT(ASCP) | June 25, 2019
Diagnostic laboratories are often asked about the sensitivities and specificities of their test offerings. While every ordered analytical test should provide important clinical insight and diagnostic information for the care of patients, the terms sensitivity and specificity are not always used consistently among the clinical community. One of the reasons for the confusion is that these terms apply to analytical measurement, as well as to clinical accuracy.
First, we’ll address analytical sensitivity and specificity. Accredited laboratories that adhere to the regulatory quality standards will rigorously validate each quantitative test offering to determine its ability to detect a range of quantities of the compound of interest. The lower limit of quantitation for each analyte is a measure of analytical sensitivity. For some hormones tests, the method is able to measure as low as 0.5 pg/mL, which is 500 parts per trillion, a very sensitive assay. For some medical conditions, this degree of analytical ultrasensitivity is needed to distinguish between adequate levels of a biomarker and unconcealed deficiencies. Analytical specificity relates to the ability of a test to measure the compound of interest. For example, for the measurement of estradiol, we do not want other estrogens to be measured as estradiol; that would not be specific. To ensure analytical specificity, next generation methods are employed with principles in chromatography, tandem mass-spectrometry, and immunoassays with monoclonal antibodies that are designed to measure the compounds of interest with minimal cross-reactivity or interferences. Every validated quantitative assay performed in accredited laboratories should also be assessed for common interfering substances to assure the highest degree of analytical specificity.
Next, we’ll address clinical sensitivity and specificity. These are measures of the ability of a test to detect a disease state or clinical condition, and are used to gauge the positive or negative predictive value of a single test. If a test is used to screen for a known disease, the sensitivity and specificity are generally known. One such example is the marker tissue transglutaminase antibody (tTG-IgA) as a screening tool for Celiac Disease, which in clinical trials has been determined to have 95% sensitivity and 95% specificity as a standalone test to identity patients with celiac disease1. Because both sensitivity and specificity approach 100%, this marker is recommended in current clinical guidelines as providing diagnostic information for celiac disease. For the biomarker fecal calprotectin, elevated levels have been demonstrated to provide 93% sensitivity and 96% specificity in children to differentiate between inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS) according to published studies2. One must keep in mind that these reports of clinical sensitivity and specificity are tied to clinically confirmed diagnoses of the published trials, and are influenced by the study population of participants. Ultimately, the positive predictive value and negative predictive value of a test for a specific disease state need to be understood, and relate to the overall prevalence of a disease in the general population. More simply stated, one needs to ask if a test has ruled out a disease or condition, or identified the likelihood of a disease or condition.
Comprehensive tests profiles, such as the Comprehensive Stool Analysis, are meant to help identify the common underlying causes of gastrointestinal (GI) ailments. As no single underlying disease state is the cause of all GI ailments, one cannot estimate the sensitivity or specificity of the test. The comprehensive nature of the test is designed to identify or rule out a number of conditions, such as exocrine pancreatic insufficiency, parasitic infections, microbial pathogens, intestinal dysbiosis, inflammatory conditions, or increased intestinal permeability. However, the percent of profiles that have a positive finding is not a measure of sensitivity or specificity of the profile, but an indication that a treatment may be beneficial or that additional testing may be needed. Thus, while emphasis may be placed on certain tests for their ability to screen for specific disease states, one must recognize the value of proven test batteries that are designed to provide comprehensive answers to more generalized clinical symptoms.
Rubio-Tapia A, Hill ID, Kelly CP, et. al. ACG Clinical Guidelines: Diagnosis and Management of Celiac Disease. Am J Gastroenterol 2013; 108:656–676.
Walsham NE, Sherwood RA. Fecal calprotectin in inflammatory bowel disease. Clin Exp Gastroenterol. 2016:9 21–29.