What this test measures
Arsenic testing measures the metalloid arsenic, by ICP-MS, in whole blood (for acute exposure within 1–2 days), 24-hour urine (for chronic exposure — the preferred matrix), or hair (for very long-term exposure). Critically, arsenic exists in different chemical forms: inorganic arsenic (As III, As V — highly toxic), methylated metabolites (MMA, DMA — moderately toxic), and organic arsenic in seafood (arsenobetaine, arsenocholine — non-toxic, excreted unchanged).
A total urine arsenic without speciation can be misleading because a seafood meal alone can raise total arsenic well above reference. Urinary arsenic speciation isolates the inorganic + methylated fraction, which reflects true toxicological exposure.
Why it matters
India has one of the world's largest populations exposed to arsenic-contaminated groundwater. Chronic arsenic poisoning ("arsenicosis") affects millions across West Bengal, Bihar, Uttar Pradesh, Jharkhand, Assam and the Ganga plain — caused by tube-well water with arsenic concentrations far exceeding the WHO guideline of 10 µg/L. Long-term exposure causes skin lesions (palmar/plantar hyperkeratosis, hyperpigmentation), peripheral neuropathy, chronic lung disease, cardiovascular disease, diabetes and several cancers (skin, lung, bladder, liver).
AIIMS and the School of Tropical Medicine Kolkata have documented thousands of arsenicosis cases. Testing supports diagnosis in symptomatic patients from affected districts, occupational health surveillance (semiconductor, smelter, pesticide workers), and forensic / acute poisoning evaluation. Testing in asymptomatic, low-risk populations is not routinely indicated.
How to prepare
Avoid all seafood, shellfish, seaweed and rice for at least 48–72 hours before urine testing (these contain organic arsenic that elevates total but not speciated levels). Stop multivitamins and herbal/ayurvedic supplements for 72 hours. For 24-hour urine collection, use a trace-element-free container provided by the lab; discard the first morning sample and collect every urine for 24 hours.
Markers & reference ranges
Reference ranges below are typical adult values. Your lab's reported range may differ slightly based on the assay platform and patient demographics — always read your report against the range printed on it.
| Marker | Normal range | If low | If high |
|---|---|---|---|
| Total Arsenic (Urine) (µg/g creatinine)[1][2] | < 50 µg/g (if seafood avoided) | Normal background. | Elevated total arsenic requires speciation. High inorganic + MMA + DMA fraction (>35 µg/g creatinine) suggests true environmental or occupational exposure. High arsenobetaine alone is from seafood and is benign. |
| Inorganic Arsenic (As III + As V) (µg/g creatinine)[1] | < 10 µg/g | Background. | Direct measure of toxic arsenic intake — usually from groundwater. >10 µg/g indicates significant exposure; >35 µg/g suggests very high exposure with risk of arsenicosis. |
| Whole Blood Arsenic (µg/L) | < 12 µg/L | Background. | Useful only for acute exposure (last 1–2 days) — arsenic clears rapidly from blood. For chronic exposure use urine speciation or hair. |
Arsenic — which matrix for which scenario
| Scenario | Best matrix | Why |
|---|---|---|
| Suspected acute poisoning | Whole blood + urine | Both rise quickly |
| Chronic groundwater exposure | 24-hr urine with speciation | Detects toxic inorganic fraction |
| Historical exposure (months past) | Hair | Arsenic deposits in keratin |
| Occupational surveillance | Spot urine speciation, end-of-shift | Standard biological monitoring |
| Seafood consumer screen | Speciation essential | Organic arsenic harmless |
Frequently asked questions
Why does fish raise arsenic levels?
Fish and shellfish contain organic arsenic (arsenobetaine) which is harmless but inflates total arsenic results. Speciation distinguishes this from toxic inorganic forms. Always avoid seafood for 48–72 hours before testing.
I live in an arsenic-affected district — should I be tested?
If you use tube-well water and have skin lesions, neuropathy, or chronic illness consistent with arsenicosis, yes — with urinary speciation. Asymptomatic family members should rely on water testing and water source change as the priority.
What is the WHO safe level in drinking water?
10 µg/L is the WHO guideline. India's permissible limit was revised to 10 µg/L in revised BIS standards (older standard was 50 µg/L). Many tube wells in affected districts still exceed these limits.
Can chronic arsenic be reversed?
The most important intervention is removing exposure (switch to safe water — community filters, deep tube wells, surface water with treatment). Skin lesions can partially regress; established cancer and cardiovascular complications do not reverse.
Is chelation useful?
Chelation (DMSA, DMPS) is used in acute high-dose poisoning. For chronic environmental exposure, source removal — not chelation — is the standard intervention.
How long does the report take?
Speciated urine arsenic typically takes 5–7 days.
Related Toxicology / Trace Elements tests
Tests commonly ordered alongside ARSENIC, or that help interpret an unexpected result.
Sources & references
- ATSDR — Arsenic Toxicological Profile · accessed 2026-05-30T00:00:00.000Z
- WHO — Arsenic Fact Sheet · accessed 2026-05-30T00:00:00.000Z
- ICMR — Arsenic in West Bengal Groundwater · accessed 2026-05-30T00:00:00.000Z
- Mayo Clinic Labs — Arsenic Speciation · accessed 2026-05-30T00:00:00.000Z
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