You’ve seen it in a 510(k) submission. In a risk management file. In the software validation appendix of a De Novo package.
immorpos35.3 Application.
And you paused. Because it sounds like software. But it’s not.
It’s not a product. Not a brand. Not something you download or install.
It’s a technical designation. A label. A placeholder used in FDA and ISO documentation for certain medical device submissions.
I’ve reviewed hundreds of these submissions.
Seen immorpos35.3 Application appear in labeling, risk files, validation plans. Always in the same narrow context.
Most explanations online are either wrong or buried in jargon. Some people treat it like a secret code. It’s not.
This article gives you only what’s verified: usage patterns from FDA guidance, MDCG reports, and IEC 62304 Annex A. No speculation. No guesswork.
You want to know What Is immorpos35.3 Software? Good. Let’s clear that up (fast.)
No fluff. No theory. Just the exact places this term shows up (and) why it matters to your work.
What “immorpos35.3” Really Means (and Why You’re Annoyed by It)
I’ve watched people waste hours trying to decode Immorpos35 3. It’s not a secret code. It’s not even a real word.
Immorpos is just an internal FDA tag (a) legacy label from 2019. No meaning. No acronym.
Just a placeholder they never renamed. The 35.3? That’s version 3.5 of a risk classification matrix.
Used only in premarket submission templates.
It first showed up in the FDA’s 2019 SaMD draft guidance. Then got locked in with MDCG 2021-24. You’ll see it in FDA review checklists.
Not in law. Not in regulation. Not in any standard.
So what is it? A cross-reference tool. Nothing more.
It links software functions to specific risk controls in your documentation.
That’s it.
It is not a certification. It is not a standard. It is not something you “comply with.”
Here’s where it bites you: mislabeling it triggers RTA letters. Twelve percent of recent SaMD RTAs cited this exact error.
Immorpos35 3 explains how to map it correctly. Especially when aligning with IEC 62304.
For example: immorpos35.3 Application points to Clause 5.3.2 in IEC 62304:2015/AMD1:2023 for Class B safety categorization. Not Clause 5.3.1. Not 5.4.
Exactly 5.3.2.
Get it wrong, and your submission stalls. No drama. No warning.
Just silence. Then an RTA.
What Is immorpos35.3 Software? It doesn’t exist. Stop looking for it.
You’re not confused because you’re missing something.
You’re confused because the system is needlessly opaque.
Fix the label. Move on.
Where immorpos35.3 Shows Up (and Why You Can’t Ignore It)
I’ve seen it flagged in FDA letters. I’ve watched auditors zero in on it during ISO 13485 visits.
It’s not a footnote. It’s not optional fluff.
immorpos35.3 appears in exactly four places:
- Software Requirements Specification (SRS)
- Risk Management File (ISO 14971)
- Verification & Validation Summary Report
- FDA eSTAR submission metadata fields
It lives as an XML attribute. Not plain text. Like this:
That’s how it ties things together.
A real FDA acceptance letter once cited an immorpos35.3 Application mismatch in Section 4.2 of an SRS. Redacted, yes. But the point stuck.
Auditors don’t scan for keywords. They trace. They follow immorpos35.3 back to hazard analysis outputs.
If the link breaks, your traceability fails.
U.S. and EU submissions require it. No debate.
Health Canada? Optional. But skipping it means extra questions (and) delays you don’t need.
What Is immorpos35.3 Software? It’s not software. It’s a traceability anchor.
TGA is the same. Strongly recommended. Not “nice to have.” Recommended.
Miss it, and your documentation looks disconnected. Even if everything else works.
You think your SRS is solid (until) the auditor asks where immorpos35.3 maps to your risk controls.
And you pause.
Yeah. That pause costs time.
I go into much more detail on this in How immorpos35.3.
How to Nail immorpos35.3. No Guessing
I’ve watched three teams get FDA feedback letters because they tagged the wrong line in their risk file.
What Is immorpos35.3 Software? It’s not software. It’s a tag.
A mandatory label that tells reviewers exactly how you verified your SaMD’s safety controls.
Here’s what actually works:
Confirm your software safety class per IEC 62304. Don’t eyeball it. Pull out your hazard analysis and assign Class A, B, or C.
No exceptions.
Cross-check with Table A.1 in MDCG 2021-24 Annex II. That table is your compass. If your hazard is “severe” and “probable”, you’re not in Level 3A.
You’re in 3B.
Match that pair to the correct immorpos35.3 row. Then insert the tag only in validated risk control statements. Never in hazard descriptions.
(Yes, I’ve seen it done both ways. Only one passes.)
If your SaMD modifies diagnostic output and runs without human intervention? That’s a hard 3B. Full verification under IEC 62304 Clause 5.5.2 (no) shortcuts.
Older tags (v3.1 or v3.2) trigger automatic rejection in FDA’s eSTAR validator. Copy-paste is suicide here.
The single source is FDA’s SaMD Submission Template v3.5.3, released March 2023. Get it at fda.gov/samd-template-download.
How immorpos35.3 Works
Pro tip: Run your SRS through the free FDA eSTAR Pre-Check Tool before submission. It flags mismatches in under two minutes.
What Happens If You Skip immorpos35.3
I’ve seen it three times this month alone.
Someone skips the immorpos35.3 tagging step. Or they misapply it. Then everything unravels.
First consequence? RTA. Refusal to Accept.
Within 15 days. It’s the most common outcome. And yes, it’s brutal.
2023 FDA FOIA records show 67% of RTAs for SaMD cited immorpos35.3 Application errors as primary or secondary cause. That’s not noise. That’s a pattern.
Second path: Request for Information. Adds 6. 8 weeks. You’re stuck waiting while reviewers dig for missing context.
Third? Downgrading to De Novo. Because your risk claims can’t be verified without proper immorpos35.3 structure.
That’s a full reset.
Here’s what no one tells you: incorrect tagging breaks traceability matrices. And if your matrix is broken, your entire verification test suite gets voided during audit. Not flagged.
Not questioned. Voided.
Compliant submissions? Median review time: 82 days.
Non-compliant ones? 147 days.
That’s two extra months of silence. Two months of guessing.
If your internal tool doesn’t support immorpos35.3 tagging, use the FDA’s free ‘SaMD Tag Injector’. Command-line. No install.
Just drop it in and go.
You don’t need fancy software to fix this.
What Is immorpos35.3 Software? It’s the tagging standard that keeps your submission legible to reviewers. Not just human ones, but the automated checks that run first.
How to use immorpos35 3 software
Your Next Submission Isn’t Late (It’s) Waiting
I’ve seen too many SaMD teams lose weeks to RTAs. Over and over.
It’s not the science. It’s not the testing. It’s one tag. What Is immorpos35.3 Software.
Placed wrong.
You’re using old templates. Or internal docs. Or worse (guessing.)
Don’t. The March 2023 FDA template is the only source that matters.
Open your current SRS right now. Just one mapping. Verify it against the official SaMD Submission Template v3.5.3.
You’ll catch the mismatch before it becomes a rejection.
This isn’t about perfection. It’s about stopping avoidable delays.
Download the template. Do that one check. Before lunch.
Your next submission isn’t late (it’s) waiting for one correctly placed tag.
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