Interpreting the BMD Your bone mineral density (BMD) test result is compared with two norms, "young normal" and "age-matched." Young normal, known as your T-score, compares your BMD test result to the optimal or peak density of a 30-year-old healthy adult. Age-matched, known as your Z-score, compares your BMD test result with what is expected for someone your age and with a similar body size. Among older adults, however, low BMD is common, so comparison with age-matched norms can be misleading. Health Tips from Dr. Healy: Video: What you need to know about arthritis pain medication Choose another disease or condition... Allergic Rhinitis Allergies, Food Allergy & Asthma Center Alzheimer's Disease Anxiety Aortic Aneurysms Arrhythmia Arthritis, Osteo- (OA) Arthritis, Rheumatoid (RA) Asthma Atopic Dermatitis Attention Deficit Hyperactivity Disorder (ADHD) Back Pain Brain Tumor Bones, Joints & Muscles Center Breast Cancer Brain & Behavior Center Brain Tumor Cancer Center    Brain Tumor    Breast Cancer    Cancer Prevention    Clinical Trials    Colorectal Cancer    Endometrial Cancer    Living With and Beyond Cancer    Lung Cancer    Prostate Cancer    Skin Cancer Cardiomyopathy Cataracts Cholesterol Control Clinical Trials Chronic Obstructive Pulmonary Disease (COPD) Colorectal Cancer Congenital Heart Disease Congestive Heart Failure (CHF) Coronary Artery Disease (CAD) Crohn's Disease Depression Diabetes Center Diabetes, Type 1 Diabetes, Type 2 Digestive Disorders Center Eczema Endometrial Cancer Erectile Dysfunction (ED) Eye & Vision Center Fibromyalgia Food Allergies Gallstone Disease Gastroesophageal Reflux Disease (GERD) GERD Glaucoma Hay Fever Headache Heart Center Hepatitis A Hepatitis B Hepatitis C High Blood Pressure Hypertension Hypertrophic Cardiomyopathy (HCM) Impotence Insomnia Irritable Bowel Syndrome (IBS) Living With and Beyond Cancer Losing Weight Lung Cancer Macular Degeneration Memory Loss Osteoarthritis (OA) Osteoporosis Parkinson's Disease Peptic Ulcer Prediabetes Prostate Cancer Respiratory Disorders Center Restless Legs Syndrome (RLS) Rheumatoid Arthritis (RA) Sexual & Reproductive Health Center Sinusitis Skin Cancer Sleep Apnea Sleep Center Stroke Type 1 Diabetes Type 2 Diabetes Ulcerative Colitis (UC) Weight Control See the top online resources for information about bones, joints &, muscles More about osteoporosis Osteoporosis Clinical Trials-Related Information Email this page Print this section

Scores below the norm are indicated in negative numbers. For example, a score from -1 to -2.5 indicates low bone mass, or osteopenia, and a score of below -2.5 indicates osteoporosis. For most BMD tests, a drop of one unit equals a 10 to 12 percent decrease in bone density. If the Z-score is especially low, your physician may need to order further tests to make sure that other processes are not causing the low density, rather than primary osteoporosis.

This BMD measurement is not the only thing that indicates an increased risk of fracture, though it is an important tool. Talking to your physician about other matters, such as your risk of falls, is also important.