Endometriosis: my minimum evidence standard

Step 01

Endometriosis is classified in ICD-11 as a disease of the genitourinary system, and its pain as secondary to it

ICD-11 classification

In ICD-11, the World Health Organization's classification of diseases, endometriosis sits with the diseases of the genitourinary system, coded by where the disease is found. The pain it causes is classified separately, as chronic secondary visceral pain from persistent inflammation: pain that is a consequence of the disease rather than a condition in its own right.

This matters for your file. The impairment is the disease and what it does in the body, and pain is one of its effects. A strong file names the site or sites of disease and the pain code, and says which findings relate to which.

Adenomyosis, which often occurs alongside endometriosis, will have its own page.

The next step is what's driving the pain.

Step 02

Endometriosis pain has more than one mechanism, and the amount of disease doesn't predict how much pain there is

Pain mechanism

Pain is classified by mechanism: nociceptive (from tissue), neuropathic (from nerve injury or disease), or nociplastic (from altered pain processing in the nervous system). The Australian guideline states that endometriosis pain “may be neuropathic, nociceptive or nociplastic and may encompass one or all three”. Lesions release inflammatory substances that sensitise nociceptors, the nerve endings that respond to potential harm; lesions can involve nerves; and persistent input can change how the spinal cord and brain process it (central sensitisation), which can spread sensitivity to neighbouring pelvic organs (McNamara et al 2021).

The amount of disease a surgeon sees doesn't tell you how much pain a person has. Some people with severe pain have minimal disease, and some with extensive disease have little pain. A file that relies on a surgical stage alone can undersell you. A strong file records the pain and what it stops you doing directly, and says which mechanism each treatment was aimed at.

The next step is the criteria the diagnosis is checked against.

Step 03

Endometriosis is diagnosed against the Australian Living Evidence Guideline

Diagnostic criteria

AAPT has not published criteria for endometriosis. The recognised Australian standard is RANZCOG's Australian Living Evidence Guideline: Endometriosis (v2.3, August 2026). It has changed how diagnosis works: surgery “is not required as a first-line option to diagnose endometriosis”, and transvaginal ultrasound is the recommended first investigation, with MRI where ultrasound isn't suitable.

A surgical stage describes the disease, not the pain or what you can do. The guideline doesn't recommend staging systems to guide the treatment of pain. A strong file records the stage but doesn't rely on it. It also records which other causes of pelvic pain were considered, for example adenomyosis, irritable bowel syndrome, bladder pain syndrome and pelvic floor muscle dysfunction. Several of these often occur alongside endometriosis, and a file that says which symptoms belong to which condition is much easier to read.

Once the diagnosis is settled, the question most refusals come down to is what has been tried.

Step 04

An endometriosis treatment history is easiest to read when it covers the nine elements of pain management

Treatment history · s 24(1)⁠(b)

Whether the NDIS accepts an impairment as permanent usually comes down to the treatment record. Endometriosis treatment usually combines hormonal treatment, surgery and pain management, and none of them reliably removes the disease for good. The Cochrane review found it “uncertain whether laparoscopic surgery reduces overall pain” compared with diagnostic laparoscopy alone. So the record of what was done, how often, and what happened afterwards, including any return of symptoms after surgery, matters more than a list of procedures. I check it against the nine elements of pain management (HEAPPPPSS). For each one, the table names a published source, Australian where one exists. For a support request, the same record shows where treatment ends and disability support begins, which is how the NDIS decides whether the health system should fund it instead.

For each element in your file, the NDIS looks for what was done and what happened, in pain and in function. For surgery, that means the date, what was found and removed, and how long any improvement lasted. For hormonal treatment, what was tried, for how long, and why it was stopped. If an element never appears, the file says nothing about it, and the NDIS decides what that silence means.

Permanence is one requirement. Function is the other one an endometriosis file most often has to show.

Endometriosis function is shown best across a whole day and the week that follows, not in one appointment

Function over time · s 24(1)⁠(c)

Endometriosis pain often follows a monthly pattern, with pain between periods as well, so an appointment in a good week sees a good week. A strong file shows which days of the cycle are hardest, how many days a month function is reduced, and whether pain between periods has become constant. Four weeks of recording covers about one cycle; two cycles show whether the pattern repeats.

A strong file follows what happens after a run of ordinary activities. I follow up at 24 hours, 72 hours and 7 days.

For an access request, I then match what your file shows to the six activity domains in s 24(1)⁠(c), the areas of daily life the NDIS assesses. For a support request, the same record shows what the support keeps you doing and what slips without it. Either way, that's done for each person, not for each condition.

There are two ways to start now.