Fibromyalgia Tender Points: What They Were, Why They Were Dropped, and What Replaced Them

The 18 tender points are probably the most recognizable feature of fibromyalgia in public understanding. A clinician pressing specific body spots with their thumb, the patient wincing, and a count determining the diagnosis. This image shaped how fibromyalgia was understood, diagnosed, and sometimes dismissed for over two decades. That the current criteria no longer use tender points is not widely known outside rheumatology, and understanding why they were abandoned clarifies what fibromyalgia actually is [4].

The history of tender points is, in a sense, a case study in how diagnostic criteria can both help and harm. They gave fibromyalgia legitimacy as a classifiable condition at a time when many clinicians doubted it existed. They also reduced a complex, multisystem illness to a single physical test, and the consequences of that reduction took years to become fully apparent.

Where the Tender Points Came From

The idea that certain body sites are reliably more tender in people with widespread musculoskeletal pain predates the formal fibromyalgia criteria by decades. Smythe and Moldofsky identified specific body sites where people with fibrositis (as it was then called) were consistently more tender than healthy controls [6]. Their work in the late 1970s established the concept that would become the diagnostic cornerstone of the field: discrete anatomical locations where pain on palpation distinguished fibrositis patients from people with other rheumatic conditions.

Wolfe and colleagues formalized these into the 1990 ACR classification criteria: 18 specific anatomical sites (9 pairs, bilateral), examined by pressing with the thumb at approximately 4 kg of force. If the patient reported pain (not just discomfort) at 11 or more of the 18 sites, and had widespread pain for at least three months, the criteria were met [1].

The 18 sites included the occiput, low cervical spine, trapezius, supraspinatus, second rib, lateral epicondyle, gluteal, greater trochanter, and medial knee, each examined on both sides. The 4 kg threshold was roughly the amount of pressure needed to blanch the examiner’s thumbnail. The specific locations were chosen because they best discriminated fibromyalgia patients from controls in the multicenter study that developed the criteria; they were not derived from a theory about why those sites should be tender, and indeed no convincing mechanistic explanation for why those specific 18 locations was ever established.

What the Research Showed

The tender points worked well for what they were designed for: distinguishing fibromyalgia from other rheumatic conditions in a research classification context. The 1990 criteria had a sensitivity of 88% and specificity of 81% for separating fibromyalgia from conditions like rheumatoid arthritis and osteoarthritis in the clinical settings where they were developed [1]. For researchers who needed a consistent way to define study populations, the criteria served that purpose.

But problems emerged when the criteria moved from research classification to clinical diagnosis, a transition that the original authors had not intended but that the field made inevitable. Frederick Wolfe, the lead author of the 1990 criteria, became one of their most prominent critics. In 1997, he published data showing that tender point count was a continuous variable in clinical populations, not a bimodal one [2]. There was no natural cutoff between “fibromyalgia” and “not fibromyalgia” at 11 points. A patient with 10 tender points and severe fatigue, sleep disruption, and cognitive difficulty did not have a meaningfully different condition from a patient with 11 tender points. The 11-point threshold, which seemed to carve nature at a joint, was instead carving a bell curve at an arbitrary point on its slope.

Croft and colleagues examined tender point counts in a general population sample and found the same thing: counts were normally distributed, with no natural break separating a fibromyalgia group from the rest [3]. The 11/18 threshold was a statistical convenience, not a biological boundary. This finding had a profound implication: fibromyalgia, as defined by tender points, was not a discrete disease entity. It was the severe end of a continuous distribution of pain sensitivity that ran through the entire population. Patients near the threshold could drift in and out of the diagnosis depending on the day, the examiner, and their current stress level.

The Clinical Problems

Beyond the statistical issues, the tender point examination had practical problems that worsened over time:

Examiner variability. Different clinicians applied different amounts of pressure, positioned their thumbs at slightly different locations, and interpreted patient responses differently. The result was that the same patient could meet the criteria with one clinician and fail them with another. Inter-examiner reliability was moderate at best. The 4 kg force specification sounds precise, but in practice, clinicians’ estimates of how hard they were pressing varied widely. Some used dolorimeters (pressure-measuring devices); most used their thumbs and their best judgment.

Incomplete symptom capture. Tender points measured one dimension of fibromyalgia: pain sensitivity. They did not capture fatigue, cognitive dysfunction, sleep disruption, or the many other symptoms that define the clinical experience. A patient could have 18 tender points and minimal fatigue, or 8 tender points and disabling cognitive fog, and the criteria captured only the first. This was not merely an academic problem. It meant that the criteria described a pain condition, while the clinical reality was a multisystem illness in which pain was often not even the most disabling symptom.

Gender bias in the examination. Women have lower pressure-pain thresholds than men on average, which meant the tender point examination was more likely to be positive in women. Whether this reflected a genuine sex difference in fibromyalgia prevalence or a measurement artifact of the examination was debated. The current criteria, which do not depend on examiner-applied pressure, have narrowed the sex ratio somewhat, suggesting the tender point methodology contributed to the skew.

Clinical nonuse. Surveys of clinicians found that many diagnosed fibromyalgia without performing the tender point examination at all. They recognized the clinical pattern (widespread pain, fatigue, sleep disruption, cognitive difficulty) and diagnosed based on that pattern, while nominally attributing the diagnosis to criteria they had not actually applied. This gap between the official diagnostic method and actual clinical practice was itself evidence that the criteria did not match the clinical reality.

What Replaced Them

The 2010 revised criteria, developed by Wolfe and colleagues, replaced tender points with two patient-reported scales: the Widespread Pain Index (WPI), which counts painful body areas from a checklist of 19 regions, and the Symptom Severity Scale (SSS), which rates fatigue, unrefreshed sleep, cognitive symptoms, and somatic symptoms on a severity scale [4]. Diagnosis required either a WPI of 7 or greater and SSS of 5 or greater, or a WPI of 3 to 6 with SSS of 9 or greater, along with symptoms present for at least three months and no other disorder that would otherwise explain the pain. The 2016 revision refined these further, adding a requirement that pain be present in at least four of five body regions and clarifying the generalized pain criterion [5].

The new criteria captured the multidimensional nature of fibromyalgia rather than reducing it to pain sensitivity at specific points. They did not require a physical examination, which eliminated inter-examiner variability. They allowed for self-report administration, which made epidemiological research more feasible. And they explicitly allowed fibromyalgia to be diagnosed alongside other conditions, which the original criteria had sometimes been interpreted as prohibiting. A patient with both rheumatoid arthritis and fibromyalgia could now carry both diagnoses, which was important because central sensitization frequently complicates inflammatory conditions.

The shift also reflected a conceptual evolution. The 1990 criteria treated fibromyalgia as primarily a pain condition with a specific physical finding. The 2010 and 2016 criteria treated it as a polysymptomatic distress disorder, a condition defined by the breadth and severity of its symptom profile. This was not a weakening of the diagnosis. It was a more accurate description of the condition.

What Remains Uncertain

Whether the shift from examiner-assessed tender points to patient-reported symptom scales introduced its own biases (particularly around self-report accuracy and the possibility of over-reporting or under-reporting) is debated. Some clinicians argue that losing the physical examination component removed useful clinical information, even if the specific 11/18 threshold was arbitrary. A tender point examination, performed carefully, provides information about pain sensitivity and distribution that a checklist cannot fully capture.

Whether a future objective measure of central sensitization (quantitative sensory testing, functional MRI, blood biomarkers) could provide a more reliable diagnostic tool than either tender points or self-report scales is an active research question, though no such measure is ready for clinical use. Several candidates are under investigation: conditioned pain modulation testing, which measures the efficiency of descending pain inhibition, has shown promise in differentiating fibromyalgia from other pain conditions. Blood-based biomarkers, including cytokine profiles and micro-RNA panels, are in early-stage research. None has the sensitivity and specificity required for clinical diagnosis.

And whether the concept of tender points retains value as a clinical finding (useful information from the examination) even though it no longer serves as a diagnostic criterion is a question that different clinicians answer differently. My reading is that tenderness to palpation remains informative, particularly when assessing the degree of central sensitization, but that the specific 18-point protocol with its 11-point threshold served its purpose and was rightly retired.

Getting support for chronic pain. Chronic pain, including fibromyalgia, is a complex medical condition that deserves proper clinical attention. A GP, rheumatologist or pain specialist can help develop a management plan. The American Chronic Pain Association (theacpa.org) and the National Fibromyalgia Association (fmaware.org) have patient resources and practitioner directories.