Knowing Your CODE: Why ICD Codes Matter More Than You Think

By Kelly du Plessis, CEO, Rare Diseases South Africa

If you live with a rare disease, or care for someone who does, you have probably had this experience: a claim comes back unpaid, a benefit is paid from the wrong pool, or a life-saving treatment suddenly needs authorisation you didn't know was required. Nine times out of ten, the explanation traces back to three or four characters on a form that most patients never learn to read: the ICD code.

It sounds like small print. It is not. For our community, knowing your code can be the difference between a claim that is paid correctly and one that is rejected, delayed, or funded from the wrong benefit entirely.

What an ICD code actually is

ICD stands for the International Classification of Diseases, a system developed and maintained by the World Health Organization. South Africa currently uses ICD-10, in which every diagnosis is reduced to a short alpha-numeric code: a letter followed by numbers, sometimes with more numbers after a decimal point to add precision. Pulmonary arterial hypertension, for example, sits in a different code range to a related but distinct heart condition, and that difference matters enormously once a claim reaches your medical scheme.

Every time a doctor, specialist, or hospital submits an account to your medical scheme, that account carries an ICD-10 code. It is not optional and it is not decorative. It is how the scheme's system decides, often without a human ever looking at the claim, what the diagnosis is and how it should be funded.

How it decides whether your claim is paid, and from where

This is the part our community feels most directly. Medical schemes in South Africa are legally required to fund a defined list of conditions in full, known as Prescribed Minimum Benefits (PMBs), regardless of which plan you are on. Whether your claim is recognised as a PMB condition, and therefore paid in full without touching your day-to-day benefits or savings, depends almost entirely on the ICD-10 code attached to it.

Get the code right, and a claim for a PMB condition is funded as the law requires. Get it wrong, even by one digit, or have it reduced to a vague, non-specific code, and that same claim can be rejected outright, paid from your depleting day-to-day benefit instead of in full, or flagged for authorisation you were never told to arrange. The condition has not changed. The code has, and that alone changes the outcome.

Where rare diseases fall through the cracks

Here is the problem specific to our community. ICD-10 was built to code common conditions well. It was not built with roughly 7,000 rare diseases in mind, and by most estimates only a few hundred of them have their own specific code. Everything else gets coded under a broader category, a symptom, or an "unspecified" catch-all that does not reflect the actual diagnosis at all.

That is not just a paperwork inconvenience. A generic or symptom-based code can strip a genuinely PMB-eligible condition of its PMB status on paper, forcing patients and families into appeals, motivation letters, and ex-gratia applications simply to get funding the law already entitles them to. It also makes rare disease patients statistically invisible: if the system has no accurate way to record your diagnosis, you are not counted in the data that schemes, funders, and government use to plan services and register medicines. This is the same invisibility we see reflected nationally, where South Africa's own congenital disorder registry captures a fraction of the cases that actually exist. ICD-11 has closed much of this gap internationally, coding over ten times as many rare diseases as ICD-10, but South Africa has not yet made that transition, so for now we are working within a system that was never designed to see us clearly.

What this means for you, practically

You do not need to become a coding expert. You do need to know three things: the name of your diagnosis, the ICD-10 code your specialist has assigned to it, and whether that condition appears on the PMB list. Ask your doctor to confirm the code verbally and check that it appears correctly on every account and claim form before it is submitted. If a claim is rejected or under-paid, the first question to ask your scheme is which code they used to adjudicate it, because that single detail usually explains the outcome and gives you the starting point for an appeal.

Keep your code on record. Share it with every new provider. Quote it when you query a claim. It is a small piece of information to carry, and it puts you back in control of a process that can otherwise feel entirely out of your hands.

If you are struggling with a rejected claim, an incorrect code, or a PMB dispute, RDSA's Rare Assist and patient navigation team are there to help you work through it. You should never have to fight for funding you are legally entitled to simply because a system was not built with your diagnosis in mind. Knowing your code will not fix that system on its own, but it is the first, most practical act of self-advocacy every one of us can take today.