The Diagnostic Path: IASP Criteria

Because nociplastic pain involves a change in how the nervous system processes signals rather than a visible injury, it cannot be “seen” on a standard scan or measured in a blood test. There is no unique biomarker—like a high blood sugar level for diabetes—that definitively proves you have it ^[1][2]. Instead, doctors use clinical evaluation to determine if your pain fits this mechanism ^[3].

The Two Levels of Diagnosis

To help standardize this, the International Association for the Study of Pain (IASP) published a proposed clinical grading framework in 2021, primarily intended for chronic musculoskeletal pain. It is a clinical aid, not a definitive disease diagnosis, and categorizes your pain as either “possible” or “probable” nociplastic pain.

1. Possible Nociplastic Pain

To meet this first level, you must fulfill all four of these requirements:

• Duration: Your pain has lasted for at least 3 months ^[3].
• Distribution: Your pain is regional, multifocal (in several separate spots), or widespread ^[3]. It is not limited to one tiny, discrete point.
• Unexplained by Other Types: Your pain cannot be entirely explained by tissue damage (nociceptive) or a specific nerve injury (neuropathic)—though nociplastic and structural mechanisms frequently coexist ^[3].
• Clinical Hypersensitivity: During a physical exam, your doctor finds signs that you are extra sensitive to pressure, touch, or movement in the area where you feel pain ^[3].

2. Probable Nociplastic Pain

To move from “possible” to “probable,” you must meet the criteria above plus two additional factors:

• History of Sensitivity: You report a history of pain from things that shouldn’t hurt (like a light touch) or an exaggerated response to things that are only mildly painful ^[4].
• Associated Comorbidities: You experience at least one of the “neighboring” symptoms we discussed earlier, such as extreme fatigue, unrefreshing sleep, “brain fog,” or sensitivity to light, sound, or odors ^[4].

Quantitative Sensory Testing (QST)

While there is no blood test, some specialists use Quantitative Sensory Testing (QST) to help identify nociplastic pain. QST is a standardized way to measure how your nervous system responds to physical stimuli like pressure, heat, or cold ^[5].

• Pressure Thresholds: Measuring how much pressure it takes before you feel pain ^[5].
• Temporal Summation: Checking if repeated, mild stimuli (like a small tap) feel increasingly painful over time ^[6].
• Conditioned Pain Modulation: Testing your body’s natural “pain-filtering” system to see if it is working properly ^[6].

While QST can provide a “profile” of your sensitivity, it is not routinely necessary and is not a standalone diagnostic test. It is one tool used alongside your history and physical exam ^[7][8].

Evaluating Your Diagnosis

Nociplastic pain often involves a selective, clinician-directed evaluation to ensure other treatable conditions are identified. You can ensure your diagnosis is thorough by discussing two things:

1. A Focused Neurologic Exam: Did your doctor check your reflexes, muscle strength, and specific sensation patterns? This helps assess for large-fiber neuropathic pain. However, note that a neurologic examination cannot by itself rule out all neuropathic pain; small-fiber disorders may have limited routine examination findings ^[9][10].
2. Contextual Imaging: If you had an MRI or X-ray that showed an “abnormality” (like a bulging disc), did your doctor confirm that it actually matches your pain? Most healthy adults have some spinal anomalies on imaging that cause no pain at all ^[11]. If your pain is widespread, a focal MRI finding does not rule out nociplastic pain; rather, nociplastic and structural mechanisms may coexist ^[11][10].

If your records don’t show that your doctor looked for these specific patterns, it is a great time to ask for a more detailed assessment ^[12].