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DN4: scoring neuropathic pain in 4 questions
The 10 DN4 items in their published wording, tickable, with the score calculation and its interpretation at the threshold of 4/10. Nothing you tick leaves your browser.
Items reproduced from annexe 1 of the Haute Autorité de santé guidelines (May 2007), which publishes them after Bouhassira D et al., Pain 2005;114(1-2):29-36.
What the DN4 measures
The DN4 (Douleur Neuropathique en 4 questions, neuropathic pain in 4 questions) was built by the French neuropathic pain study group to answer a precise question: does this pain have a neuropathic component, or is it purely nociceptive? It measures neither intensity, nor impact, nor course.
Its structure comes in two parts. The first 7 items belong to history-taking : three characteristics of the pain, then four associated symptoms in the same region. The last 3 require an examination of the painful area, looking for hypoaesthesia and brush-evoked allodynia. Each positive answer is worth 1 point, each negative answer 0, for a total out of 10.
It is this second part that sets the DN4 apart from a plain symptom questionnaire, and it is the part most readily skipped. Skipping it changes the tool and changes the threshold: see below.
Scoring a patient
The questionnaire is administered by the practitioner during the consultation. Tick each item present in your patient: the score updates as you go.
DN4 questionnaire
The 10 items in the wording published by the Haute Autorité de santé. A ticked box is worth 1 point, a box left empty is worth 0.
DN4 score: 0 / 10
Score below the threshold of 4/10. As it stands, the questionnaire does not point to a neuropathic component.
History alone (items 1 to 7): 0 / 7.
No data leaves this device. The calculation happens entirely in your browser: nothing is sent to a server, nothing is recorded, and closing the tab erases everything. The copy button writes the summary to your clipboard, and nowhere else.
The threshold of 4 out of 10
The threshold used is 4 out of 10 : from 4 positive items onwards, the questionnaire concludes that the pain is neuropathic. It comes not from usage but from the construction study itself, where it is the value that jointly maximises sensitivity and specificity.
In that study, across 160 patients with a confirmed neurological or somatic lesion, the threshold of 4 gives a sensitivity of 82.9 % and specificity of 89.9 %. It is these two figures, and these alone, that have circulated ever since in the rounded form “83 % and 90 %”.
Why these values are a ceiling
The construction study compared two groups chosen to be clear-cut: 89 patients with a nerve lesion (nerve trauma, post-herpetic neuralgia, post-stroke pain) and 71 patients with a non-neurological lesion (osteoarthritis, inflammatory arthropathies, mechanical low back pain). Each case had been confirmed by two independent experts. A tool tested on clear-cut cases always performs better than on an everyday caseload, where intermediate pictures are the rule.
The measurement exists: one study recruited 291 consecutive chronic pain patients, with no preselection, then calculated the diagnostic values on the 228 for whom two doctors agreed on the nature of the pain. At the same threshold of 4/10, sensitivity falls to 75 % (95 % CI 0.68 to 0.81) and specificity to 76 % (95 % CI 0.61 to 0.86). Some fifteen points of specificity less, which means markedly more false positives than advertised.
The detail of the 63 patients set aside is worth noting: it is the share of cases where two doctors did not agree on the nature of the pain. The standard the questionnaire is compared against is itself uncertain, and that holds in the consulting room too.
What the score does not tell you
A positive DN4 says one thing: the symptoms and the signs found resemble those of neuropathic pain. Three conclusions it does not allow:
- It does not make a diagnosis. It is an orientation tool, designed to spot a neuropathic component and trigger what follows, not to replace it. The diagnosis remains clinical and assumes a lesion or a disease of the somatosensory system that is plausible given the painful area.
- It identifies no cause. A radiculopathy, an entrapment syndrome, a diabetic polyneuropathy and post-herpetic neuralgia all give the same 7/10. The score distinguishes neither the site of the lesion nor its mechanism.
- It grades nothing. An 8/10 is not a “more neuropathic” pain than a 5/10, and the variation of a score between two sessions does not measure a course: the DN4 was neither built nor validated as a follow-up tool.
A score below the threshold does not close the question
With a sensitivity of 83 % under the best conditions, roughly one neuropathic patient in six is missed, and the proportion rises when the population looks like a real caseload. Faced with a suggestive picture (a systematised topography, a history of nerve injury, pain poorly relieved by the usual analgesics), a DN4 of 3/10 warrants carrying on with the examination, not concluding.
The short version, 7 items
A version reduced to the 7 history items exists, called DN4-interview, DN4i or DN4-symptoms depending on the publication. It drops the examination: no search for hypoaesthesia, no brushing test. It was designed for situations where an examination is impossible, foremost among them postal and telephone surveys, and by extension teleconsultation.
It has its own threshold, and confusing it with that of the full DN4 distorts the result in both directions. A patient with 3 history items is below the threshold of the full DN4 but at the threshold of the short version.
| Version | Items | Threshold | What is known about it |
|---|---|---|---|
| Full DN4 | 10 (7 history, 3 examination) | 4 out of 10 | Sensitivity 82.9 % and specificity 89.9 % in the construction study. It is the validated version, and the only one whose threshold that study establishes. |
| Short version | 7 history items | 3 out of 7 most often | The construction study reports, for those 7 items taken alone, a sensitivity of 78 % and a specificity of 81 %. Less specific than the full version: that is the price of the examination dropped. |
A caveat we have not been able to lift
The threshold of 3/7 is the one found everywhere, but we have found no accessible source establishing that it is indeed at this threshold that the construction study obtains its 78 % and 81 % for the 7 history items. The only 3/7 we have been able to trace back to its measurement is that of the 2017 consecutive-caseload study, where it is an optimum calculated by that study (Youden index), and where it gives a sensitivity of 70 % and a specificity of 67 %. We would rather flag this than present a well-sourced figure and a figure passed from hand to hand with the same assurance.
Four pitfalls of administration
Score an area, not a patient
Items 8 to 10 concern the painful area. In a patient with two distinct pains, mechanical low back pain and cervicobrachial neuralgia, a single DN4 makes no sense: the descriptors of one mix with the signs of the other. One administration per painful region, and the score covers what it claims to describe.
Hypoaesthesia is compared with the healthy side
Items 8 and 9 are comparisons, not absolute measurements. Without a contralateral reference (or a proximal one when the involvement is bilateral), sensation is scored “normal” or “reduced” by guesswork, and two examiners no longer score the same thing.
Brushing is not pressure
Item 10 looks for dynamic mechanical allodynia: a light moving contact, of the brush or sliding fingertip type. Pressing means looking for something else and making ordinary nociceptive pain answer yes, with a false positive at the end of it.
The questionnaire is administered, not handed out
The validated version is filled in by the practitioner during the consultation. A patient ticking “tingling” or “numbness” on their own does not always put the same content as you behind the word. The short version does not escape this limit, it shifts it: that is precisely why it is less specific.
In practice
- Record the score and the version used: “DN4 6/10” and “DN4 history 4/7” do not say the same thing.
- Record the region scored when the patient has several pains.
- A score at the threshold in a patient with no plausible nerve lesion should prompt a re-reading of the items rather than a conclusion.
- Do not follow a patient on the trend of their DN4: that is not what it measures.
- Spotting a neuropathic component changes management: it warrants a medical referral, and it often explains why the usual analgesics are not enough.
References
- Bouhassira D, Attal N, Alchaar H, Boureau F, Brochet B, Bruxelle J, Cunin G, Fermanian J, Ginies P, Grun-Overdyking A, Jafari-Schluep H, Lantéri-Minet M, Laurent B, Mick G, Serrie A, Valade D, Vicaut E. Comparison of pain syndromes associated with nervous or somatic lesions and development of a new neuropathic pain diagnostic questionnaire (DN4). Pain 2005;114(1-2):29-36. PMID 15733628. Primary source: construction of the questionnaire on 160 patients, threshold of 4/10.
- Haute Autorité de santé. Prise en charge diagnostique des neuropathies périphériques (polyneuropathies et mononeuropathies multiples). Recommandations professionnelles, mai 2007, annexe 1. Publishes the questionnaire in its French wording, after reference 1: it is the source of the items reproduced on this page.
- Timmerman H, Steegers MAH, Huygen FJPM, Goeman JJ, van Dasselaar NT, Schenkels MJ, Wilder-Smith OHG, Wolff AP, Vissers KCP. Investigating the validity of the DN4 in a consecutive population of patients with chronic pain. PLoS One 2017;12(11):e0187961. PMID 29190718. Unselected consecutive caseload: 291 patients recruited, diagnostic values calculated on the 228 where two doctors agreed. Sensitivity 75 % and specificity 76 % at the threshold of 4/10.
- Bouhassira D, Lantéri-Minet M, Attal N, Laurent B, Touboul C. Prevalence of chronic pain with neuropathic characteristics in the general population. Pain 2008;136(3):380-7. PMID 17888574. Postal survey on 23,712 usable responses: the large-scale use that made a version without an examination necessary.