The location of the nine paired tender points that comprise the 1990 American College of Rheumatology criteria for<unk>  There is no single pathological feature, laboratory finding, or biomarker that can diagnose<unk>  and there is debate over what should be considered diagnostic criteria and whether an objective diagnosis is possible. In most cases, people with<unk>  symptoms may have laboratory test results that appear normal and many of their symptoms may mimic those of other rheumatic conditions such as arthritis or osteoporosis. The specific diagnostic criteria for<unk>  have evolved over time. American College of Rheumatology 1990 The first widely accepted set of classification criteria for research purposes was elaborated in 1990 by the Multicenter Criteria Committee of the American College of Rheumatology. These criteria, which are known informally as "the ACR 1990", defined<unk>  according to the presence of the following criteria: * A history of widespread pain lasting more than three months – affecting all four quadrants of the body, i.e., both sides, and above and below the waist. * Tender points – there are 18 designated possible tender points (although a person with the disorder may feel pain in other areas as well). The ACR criteria for the classification of patients were originally established as inclusion criteria for research purposes and were not intended for clinical diagnosis but have later become the de facto diagnostic criteria in the clinical setting. A controversial study was done by a legal team looking to prove their client's disability based primarily on tender points and their widespread presence in non-litigious communities prompted the lead author of the ACR criteria to question now the useful validity of tender points in diagnosis. Use of control points has been used to cast doubt on whether a person has<unk> , and to claim the person is malingering. American College of Rheumatology 2010 provisional criteria Widespread pain index (WPI) areas In 2010, the American College of Rheumatology approved provisional revised diagnostic criteria for<unk>  that eliminated the 1990 criteria's reliance on tender point testing. The revised criteria used a widespread pain index (WPI) and symptom severity scale (SSS) in place of tender point testing under the 1990 criteria. The WPI counts up to 19 general body areas in which the person has experienced pain in the preceding week. The SSS rates the severity of the person's fatigue, unrefreshed waking, cognitive symptoms, and general somatic symptoms, each on a scale from 0 to 3, for a composite score ranging from 0 to 12. The revised criteria for diagnosis were: * WPI ≥ 7 and SSS ≥ 5 OR WPI 3–6 and SSS ≥ 9, * Symptoms have been present at a similar level for at least three months, and * No other diagnosable disorder otherwise explains the pain. American College of Rheumatology 2016 revisions In 2016, the provisional criteria of the American College of Rheumatology from 2010 were revised. The new diagnosis required all of the following criteria: # "Generalized pain, defined as pain in at least 4 of 5 regions, is present." # "Symptoms have been present at a similar level for at least 3 months." # "Widespread pain index (WPI) ≥ 7 and symptom severity scale (SSS) score ≥ 5 OR WPI of 4–6 and SSS score ≥ 9." # "A diagnosis of<unk>  is valid irrespective of other diagnoses. A diagnosis of<unk>  does not exclude the presence of other clinically important illnesses." American Pain Society 2019 In 2019, the American Pain Society in collaboration with the U.S. Food and Drug Administration developed a new diagnostic system using two dimensions. The first dimension included core diagnostic criteria and the second included common features. In accordance to the 2016 diagnosis guidelines, the presence of another medical condition or pain disorder does not rule out the diagnosis of<unk> . Nonetheless, other conditions should be ruled out as the main explaining reason for the patient's symptoms. The core diagnostic criteria are: # Multisite pain defined as six or more pain sites from a total of nine possible sites, for at least three months # Moderate to severe sleep problems or fatigue, for at least three months Common features found in<unk>  patients can assist the diagnosis process. These are tenderness (sensitivity to light pressure), dyscognition (difficulty to think), musculoskeletal stiffness, and environmental sensitivity or hypervigilance. Multidimensional assessment Some research has suggested not to categorise<unk>  as a somatic disease or a mental disorder, but to use a multidimensional approach taking into consideration somatic symptoms, psychological factors, psychosocial stressors and subjective belief regarding<unk> . A review has looked at self-report questionnaires assessing<unk>  on multiple dimensions, including: * Revised<unk>  Impact Questionnaire * Widespread Pain Index * Hospital Anxiety and Depression Scale * Multiple Ability Self-Report Questionnaire * Multidimensional Fatigue Inventory * Medical Outcomes Study Sleep Scale Differential diagnosis As of 2009, as many as two out of every three people who are told that they have<unk>  by a rheumatologist may have some other medical condition instead.<unk>  could be misdiagnosed in cases of early undiagnosed rheumatic diseases such as preclinical rheumatoid arthritis, early stages of inflammatory spondyloarthritis, polymyalgia rheumatica, myofascial pain syndromes and hypermobility syndrome. Neurological diseases with an important pain component include multiple sclerosis, Parkinson's disease and peripheral neuropathy. Other medical illnesses that should be ruled out are endocrine disease or metabolic disorder (hypothyroidism, hyperparathyroidism, acromegaly, vitamin D deficiency), gastro-intestinal disease (celiac and non-celiac gluten sensitivity), infectious diseases (Lyme disease, hepatitis C and immunodeficiency disease) and the early stages of a malignancy such as multiple myeloma, metastatic cancer and leukemia/lymphoma. Other systemic, inflammatory, endocrine, rheumatic, infectious, and neurologic disorders may cause<unk> -like symptoms, such as systemic lupus erythematosus, Sjögren syndrome, ankylosing spondylitis, Ehlers-Danlos syndromes, psoriatic-related polyenthesitis, a nerve compression syndrome (such as carpal tunnel syndrome), and myasthenia gravis. In addition, several medications can also evoke pain (statins, aromatose inhibitors, biophosphonates, and opioids). The differential diagnosis is made during the evaluation on the basis of the person's medical history, physical examination, and laboratory investigations. The patient's history can provide some hints to a<unk>  diagnosis. A family history of early chronic pain, a childhood history of pain, an emergence of broad pain following physical and/or psychosocial stress, a general hypersensitivity to touch, smell, noise, taste, hypervigilance, and various somatic symptoms (gastrointestinal, urology, gynecology, neurology), are all examples of these signals Extensive laboratory tests are usually unnecessary in the differential diagnosis of<unk> . Common tests that are conducted include complete blood count, comprehensive metabolic panel, erythrocyte sedimentation rate, C-reactive protein, and thyroid function test.
Fibromyalgia
Osteoarthritis
Polymyalgia rheumatica
Rheumatoid arthritis
Complex regional pain syndrome
Myofascial pain syndrome
Thyroid disease
Calpainopathy