In Brazil, a registered product is not an available one
A model that assumes a product can be bought because it appears on a list will price something the public sector cannot actually purchase.
Registration, a mandatory coverage list, and real availability are three different things in Brazil, and a base case that treats them as one inherits a cost for a product that is not there. The check is quick once you know to make it, and it is one of the first things a careful reviewer looks for, so it is worth doing before a price is ever attached.
Registration can be expired, or never have existed
A molecule that is standard practice elsewhere may have no active registration in Brazil. Registrations that once existed can have lapsed years ago and never been renewed, so the public sector cannot buy the product, and a base case built on it is pricing an absence. The ANVISA registry settles this before anything else, and when the product is genuinely unavailable the base case moves to an alternative used in Brazilian practice rather than to a number that does not correspond to a purchase.
A mandatory list is not a supply guarantee
Brazil has lists that say what must be offered, and they are easy to mistake for lists of what is on the shelf. The ANS coverage list defines what private plans are obliged to cover, and RENAME, together with what CONITEC has incorporated, defines what the public system should make available, but neither tells you that a given service actually holds the item, buys it, or buys it at a price you can observe. What must be covered and what is routinely purchased are different questions, and only the second one has a cost you can defend.
A product can be registered for a different use
Presence in a catalogue does not confirm that the product is the comparator the model intends. The same registration can cover a different indication or format, so a product registered for one indication or format is not evidence of the variant the model intends, and counting it as one would price the wrong thing. Reading the registration, not the catalogue label, is what tells the two apart.
What this means for a base case
Availability is checked before a price is chosen, not after, and each input is placed in the right category, registered, covered, actually purchased, because they carry different evidence and different risk. Where a requested product cannot be bought, the honest output names the alternative in real use, prices that, and flags the substitution so the counterparty sees the reasoning rather than a silent swap. The number that survives review is the one that can say, in a line, what it is a price for and that the thing can be bought at all.
When a model built elsewhere needs Brazilian inputs
corina turns Brazilian public data into model-ready inputs, checking availability, reconstructing each product through the ANVISA registry, and pricing what can actually be bought, delivered in your template with a purchase-level annex and a methods note the counterparty can audit.