Transparency & Science
Methodology & Scientific Foundation
How this screening tool works, what it measures, where the methodology comes from, and what its limitations are.
What This Tool Is
MoldToxinTest is a browser-based wellness screening tool that implements two validated assessment methods — the Visual Contrast Sensitivity (VCS) test and a structured symptom cluster questionnaire — both developed and validated by Dr. Ritchie Shoemaker, MD, over more than two decades of clinical research.
It is a screening tool, not a diagnostic device. A positive result indicates patterns commonly associated with biotoxin-related illness and warrants follow-up with a qualified healthcare provider. It cannot diagnose CIRS, Lyme disease, or any other condition.
The VCS Test — FACT Protocol
The Visual Contrast Sensitivity test implemented here is based on the Functional Acuity Contrast Test (FACT®), developed by Arthur P. Ginsburg, Ph.D., and commercialized by Stereo Optical Company. FACT is the specific chart methodology used in Shoemaker's clinical research and in validated CIRS screening worldwide.
Test Architecture
Why biotoxins affect visual contrast sensitivity: Biotoxins trigger elevation of C4a (a complement split product), which causes capillary hypoperfusion in the optic nerve and retina. This preferentially damages magnocellular neurons — large, fast-conducting visual pathway neurons with high metabolic demand. These neurons are responsible for mid-range spatial frequency processing (6–12 cpd), which is exactly what FACT measures. The result is a characteristic VCS deficit at those frequencies that is measurable before other symptoms become severe.
Screen Calibration
Accurate VCS testing requires correct spatial frequencies on the user's specific display. Our calibration step calculates pixels-per-inch (PPI) using a physical reference object (credit card outline), estimates display gamma for correct contrast rendering, and sets viewing distance to 18 inches — matching the clinical standard. Gamma correction is applied to every grating patch to ensure displayed contrast matches intended contrast regardless of monitor age or settings.
Symptom Cluster Methodology
The questionnaire implements Shoemaker's 13-cluster symptom classification system, developed through statistical analysis of symptom co-occurrence across tens of thousands of CIRS patients. The 37 core symptoms were identified as differentiating CIRS cases from controls and organized into 13 clusters to maximize predictive capability.
Scoring Rules
A cluster is positive if any single symptom within it is rated ≥2 in frequency OR ≥2 in severity
Clinical threshold: ≥8 of 13 clusters positive is consistent with biotoxin illness pattern
Composite item score = frequency × severity (range 0–16), used for symptom burden tracking
Exposure history questions (52–55) determine pattern classification: mold, Lyme, post-viral, or heavy metal
Combined VCS + ≥8 clusters achieves 98.5% screening accuracy per Shoemaker 2017 clinical data
Questions use a dual Likert scale — frequency (0–4: Never to Always) and severity (0–4: None to Disabling) — anchored to a 2-week recall period. This dual-dimension approach provides treatment tracking capability while preserving the binary cluster positive/negative logic required for the threshold-based scoring.
Risk Classification System
VCS passed both eyes + fewer than 6 clusters positive + no significant exposure history
VCS passed but ≥6 clusters positive, OR borderline VCS with fewer than 8 clusters, OR significant exposure with fewer than 6 clusters
VCS failed in one eye, OR ≥8 clusters positive, OR borderline VCS + ≥6 clusters + exposure history
VCS failed both eyes + ≥8 clusters positive + confirmed exposure history
Supporting Research
The following peer-reviewed and government publications form the scientific basis for the methodology used in this tool.
Sick building syndrome (SBS) and exposure to water-damaged buildings: time series study, clinical trial and mechanisms.
Shoemaker RC, House D.
Neurotoxicology and Teratology · 2006 · 28(5):573–588 · PMID: 16962741
Foundational clinical study establishing the link between water-damaged building exposure and VCS deficits. Validated VCS as a reliable screening marker across a large patient cohort.
Detection of mycotoxins in patients with chronic fatigue syndrome.
Brewer JH, Thrasher JD, Straus DC, Madison RA, Hooper D.
Toxins (Basel) · 2013 · 5(4):605–617 · PMID: 23580077
Peer-reviewed study confirming mycotoxin presence in patients presenting with chronic fatigue and multi-system symptoms, supporting the biological basis of biotoxin-related illness patterns.
Indoor Mold: Better Coordination of Research on Health Effects and More Consistent Guidance Would Improve Federal Efforts.
U.S. Government Accountability Office.
GAO Report GAO-08-980 · 2008 · United States Government
Federal government report confirming the scale of water-damaged building exposure in the US and calling for improved research coordination on health effects — validating the public health significance of this screening area.