VCS and HLA: The Two Tests That Tell You If Mold Is Your Problem

The full CIRS workup is expensive. These two tests cost a rounding error by comparison, and between them they answer the two questions that decide whether the rest is worth running.

Test 1 — VCS (Visual Contrast Sensitivity)

What it measures: your ability to distinguish increasingly faint grey bars at five spatial frequencies, per eye.

Why it works: biotoxins impair capillary perfusion, and the optic nerve is one of the most perfusion-sensitive tissues in the body. When biotoxin load is active, contrast discrimination in the mid frequencies (rows C and D) degrades before you notice anything subjectively.

What it costs: about $15 online. Ten minutes.

How to read it: a failing pattern in the mid-range rows, especially bilaterally, is consistent with ongoing biotoxin effect. Passing does not rule mold out — a meaningful minority of confirmed CIRS patients pass.

Its best use is repetition. Run it monthly through treatment. A rising trend line is one of the few pieces of objective feedback patients get in month three, when they don't feel better yet and want to quit.

False positives to rule out: uncorrected vision, cataracts, alcohol within 24 hours, some medications, other neurotoxic exposures, and simply doing it on a badly calibrated screen in a dark room.

Test 2 — HLA-DR/DQ genotype

What it measures: the haplotype your immune system uses to present antigens.

Why it matters: certain haplotypes are strongly over-represented among people who develop chronic biotoxin illness. If the antigen never gets presented, the antibody never gets made, and the biotoxin recirculates instead of being cleared. That's the mechanism behind the entire CIRS model.

Run it once. It never changes.

What it does not do: it does not diagnose you, and it does not predict your future. Susceptibility plus exposure is what makes illness. Plenty of people carry a susceptible haplotype and stay well for life because they never lived in a water-damaged building.

What it's genuinely good for:

1. Explaining the family asymmetry — you're sick, they're fine, same house.
2. Justifying a lower future risk tolerance. If you're susceptible, a leaky basement isn't a maintenance issue, it's a health decision.
3. Ending the "it's all in your head" era of your case with an objective finding.

The sensible sequence

1. VCS ($15) — is there an active biotoxin effect right now?
2. HERTSMI-2 or ERMI on the home — is there a source?
3. HLA-DR/DQ — are you the one who can't clear it?
4. Urinary mycotoxins — what's the body burden?
5. Full CIRS panel — only once 1–4 point in the same direction.

Running step 5 first is how people spend $2,000 to learn they should have tested their basement.

Where we fit

If you're at step zero and just want a clinician-grade read on whether biotoxin illness is the thread to pull, Health Decode is $47 and covers the whole root-cause map, not just mold. If the panel is already run and you've stalled, that's a Private Concierge conversation.

Related reading

• The CIRS lab panel decoded
• The Shoemaker Protocol, explained
• Dr. Ritchie Shoemaker — hub

Medically reviewed by Dr. Nicole Rivera, Integrative Medicine Practitioner. Last reviewed August 2026. Sources: Shoemaker RC, Surviving Mold (2010); Shoemaker RC, Hudnell HK, Neurotoxicology and Teratology (2001) on visual contrast sensitivity in biotoxin illness; Biotoxin Illness protocol updates (2018–2024). This article is educational and is not a diagnosis or a treatment plan. Biotoxin protocols require clinician supervision.