Mast Cell Reactivity Test
Concept
A home-usable kit for measuring nasal mast cell reactivity — not a binary MCAS diagnostic, but a semi-quantitative reactivity score with longitudinal monitoring capability.
Motivated by the absence of any accessible, standardized way to measure mast cell reactivity outside a research setting. Current gold standard (serum tryptase) has a 1-2 hour post-reaction window and requires a blood draw. No consumer equivalent exists. See MCAS for why current diagnostic criteria are contested.
Related to Overview — same population, complementary tools. Food kit measures what’s in the food; this kit measures how reactive your cells are to it.
Core Insight
Nasal mast cells are accessible via swab or brush. Unlike gut mast cells (biopsy required) or systemic mast cells (circulate poorly), nasal mucosa mast cells can be collected non-invasively, kept viable in buffer, and provoked ex vivo. The degranulation response is measurable in a small contained volume where signal concentration is high enough for simple detection chemistry.
This sidesteps the fundamental problem with blood-based tryptase measurement — the picogram-range sensitivity requirement comes from dilution into circulation. In a 200-500µL vial, the same cells produce a nanogram-range signal. Completely different detection challenge.
The Two Output Numbers
Drop number at signal — reactivity threshold. How easily do these cells fire. Measured by incremental liberator addition (drop titration).
Total signal at endpoint — activation magnitude. How much mediator was ultimately released across the whole cell population.
These measure different things:
- Early fire + low total = few cells, very reactive
- Late fire + high total = many cells, normal threshold, large total response
- Early fire + high total = many reactive cells — classic MCAS picture
- No fire + low total = normal reactivity or poor cell capture (check with nuclear control)
Diagnostic Modes
Baseline characterization — no stabilizer pre-treatment, characterize raw reactivity and burden.
Treatment monitoring — standardized cromolyn spray pre-treatment, track reactivity score over time. Did ketotifen move your drop number? Objective answer.
The cromolyn spray is also baked into the standard protocol as a collection stabilizer — suppresses mechanical degranulation stress during swab and transfer, cleaning up baseline noise. The stabilizer becomes part of the assay definition, so the drop number always means “reactivity above the cromolyn floor.”
Status
- Concept developed
- Biology validated (nasal MC accessibility, ex vivo degranulation precedent)
- Detection chemistry identified
- Protocol designed
- Cell yield feasibility experiment (Splatspace)
- Viability window characterization
- Liberator dose-response calibration
- Background histamine washout validation
- Vision model cell counting prototype
- Hand centrifuge rotor design and print
- Full kit prototype
Vault Structure
Foundational Biology
- MCAS Biology — compact mast cell reference (links into full education wiki)
Research
- Intervention Targets — therapeutic target landscape
- Existing Diagnostics — why current methods are inadequate
- H4 Blocker Compounds — ZPL-3893888, JNJ-39758979, toreforant
- Nasal Mast Cell Precedent — existing literature on nasal MC harvest
Protocols
- Feasibility Experiment — Splatspace first experiment
- Collection Protocol — spray, brush, transfer
- Drop Titration — liberator addition, signal detection, scoring
- Nuclear Control — viability verification
Hardware
- Hand Centrifuge — motor options, 3D printed rotor, G-force math
- Vision Model — USB microscope, cell classification, degranulation scoring