Reagent Testing Guide
Testing, measuring, and preparation supplies that reduce risk. Knowing what you have and how much you're taking are the two most impactful harm reduction practices.
reagent testing kits
What a reagent test can and cannot tell you. A reagent reaction is presumptive, not confirmatory — the color suggests which substance class is likely present. It cannot tell you the dose or purity, whether an adulterant is also present, or whether the substance contains fentanyl — reagents do not detect fentanyl(use a fentanyl test strip for that). Treat “no reaction” as unknown, not safe; cross-check with a second reagent. A reaction that matches your expected substance still does not mean a dose is safe — start low regardless. Only lab analysis (GC–MS / FTIR) is confirmatory.
Marquis
detects — MDMA/MDA, amphetamines, DXM, opioids
likely colors — MDMA → purple/black. Amphetamine → orange/brown. DXM → grey/black. No reaction may indicate a novel substance.
notes — The most broadly useful single reagent. Start here if you only buy one.
Mecke
detects — MDMA/MDA, opioids, 2C-B
likely colors — MDMA → blue/black. Opioids → yellow/green. 2C-B → yellow/green.
notes — Cross-checks Marquis results. Distinguishes some substances Marquis cannot.
Ehrlich
detects — LSD and other indoles (psilocybin, DMT)
likely colors — LSD → purple. Psilocybin → purple. DMT → purple. No reaction = not an indole (possible NBOMe).
notes — Essential for any blotter or tab. NBOMes are active at LSD doses and can be fatal. A clear Ehrlich reaction suggests an indole is present; no reaction is a red flag. Ehrlich lowers but does not eliminate NBOMe risk — confirm with Hofmann and treat any ambiguity as unsafe.
Mandelin
detects — Ketamine, PMA/PMMA, amphetamines
likely colors — Ketamine → orange. PMA → green/black. Amphetamine → green.
notes — PMA/PMMA is a dangerous MDMA adulterant. Mandelin helps identify it.
Hofmann
detects — LSD specifically (distinguishes from other lysergamides)
likely colors — LSD → blue. Other lysergamides may give different or no reaction.
notes — More specific than Ehrlich. Use both for highest confidence on blotter identification.
Simon’s A/B
detects — Distinguishes MDMA from MDA
likely colors — MDMA → blue. MDA → no reaction.
notes — Use after Marquis gives a presumptive positive. Helps narrow down the specific substance.
fentanyl test strips
Fentanyl contamination is the leading cause of overdose death in North America. Test everything — including substances you wouldn't expect to contain fentanyl (cocaine, pressed pills, counterfeit prescriptions).
–Fentanyl test strips detect fentanyl and many fentanyl analogues in any substance
–Dissolve a small amount of the substance in water (10mg in 5ml), dip the strip, wait 2–5 minutes
–One line = POSITIVE for fentanyl. Two lines = negative. No lines = invalid test, retry
–Test strips are not 100% accurate — they may miss some novel fentanyl analogues
–A negative result reduces risk but does not eliminate it — fentanyl can be unevenly distributed in a batch
–Even trace amounts of fentanyl can be fatal, especially for opioid-naive individuals
–Test strips are legal in most US states — check local laws as regulations vary
–Available from DanceSafe, BTNX, and many harm reduction organizations (often free)
–A negative strip is not a guarantee — if you use, treat the substance as if fentanyl may be present: start low, go slow, keep naloxone on hand, and never use alone
milligram scales
what to look for
–0.001g (1mg) precision minimum — 0.01g scales are not precise enough for most substances
–Calibration weight included or available
–Tare function (zero out container weight)
–Windshield or draft cover for accurate readings at milligram level
best practices
–Calibrate before each session using the included calibration weight
–Weigh on a stable, level surface away from drafts and vibrations
–Never eyeball a dose — the difference between a common and dangerous dose can be invisible
–Use weighing paper or a small container, not your finger
–Weigh each dose individually — don’t divide a bulk amount by eye
recommended models
–Gemini-20 — widely recommended for harm reduction, 0.001g precision, ~$25
–AWS Gemini-20 — same unit, different branding
–Any milligram scale with good reviews and included calibration weight
volumetric dosing
For substances active at very low doses (below 5mg), milligram scales are not precise enough. Volumetric dosing dissolves a known quantity in a measured liquid volume for accurate sub-milligram measurement.
–Dissolve a known amount of substance in a measured volume of solvent (distilled water, propylene glycol, or ethanol depending on solubility)
–Example: 10mg dissolved in 10ml = 1mg per ml. Use an oral syringe to measure precise doses
–Essential for substances active below 5mg where scales become unreliable
–Verify the substance is fully dissolved — undissolved material means uneven dosing
–Store solutions in amber glass bottles away from light and heat
–Label clearly: substance, concentration (mg/ml), date prepared, solvent used
–Common use cases: LSD microdosing, research chemicals, any substance with a narrow dose-response curve
safer use supplies
– Reagent testing kitsSubstance verification — know what you’re taking
– Fentanyl test stripsScreen for fentanyl contamination in any powder or pressed pill
– Milligram scaleAccurate dosing — never eyeball
– Oral syringes (1ml, 5ml)Volumetric dosing for precise sub-milligram measurement
– Sterile water + filtersPreparation supplies for IV use (if applicable) — harm reduction, not endorsement
– Naloxone (Narcan)Opioid overdose reversal — available without prescription in most US states
– BenzodiazepinesTrip-abort option for psychedelic emergencies (with prior consent)
– Electrolyte drinksHydration during stimulant or MDMA use — avoid overhydrating with plain water
– ThermometerMonitor body temperature during stimulant or MDMA use
– Blood pressure cuffMonitor cardiovascular status during stimulant use
where to get supplies
– DanceSafeReagent kits, fentanyl strips, drug checking services at events
– Bunk PoliceReagent testing kits and spot testing supplies
– BTNXManufacturer of fentanyl test strips
– The LoopUK-based drug checking service at festivals
– Drug Checking ServicesFree lab-grade testing in some jurisdictions — check local availability