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Test Code HMNA Heavy Metals, Nails

Reporting Name

Heavy Metals, Nails

Useful For

Detection of nonacute arsenic, mercury, and lead exposure

Profile Information

Test ID Reporting Name Available Separately Always Performed
ASNA Arsenic, Nails Yes Yes
PBNA Lead, Nails Yes Yes
HGNA Mercury, Nails Yes Yes

Method Name

Inductively Coupled Plasma-Mass Spectrometry (ICP-MS)

Performing Laboratory

Mayo Medical Laboratories in Rochester

Specimen Type


Specimen Required

Supplies: Hair and Nails Collection Kit (T565)

Specimen Volume: 0.2 g

Collection Instructions:

1. Prepare and transport specimen per the instructions in the kit or see Collecting Hair and Nails for Metals Testing in Special Instructions.

2. Clippings should be taken from all 10 fingernails or toenails.

Additional Information: If known, indicate source of nails (fingernails or toenails).

Specimen Minimum Volume

0.05 g

Specimen Stability Information

Specimen Type Temperature Time
Nail Ambient (preferred)

Reject Due To









Reference Values


0-15 years: not established

≥16 years: 0.0-0.9 mcg/g of nails



0.0-3.9 mcg/g of nails

Reference values apply to all ages.



0-15 years: not established

≥16 years: 0.0-0.9 mcg/g of nails

Day(s) and Time(s) Performed

Tuesday; 3 p.m.

CPT Code Information




LOINC Code Information

Test ID Test Order Name Order LOINC Value
HMNA Heavy Metals, Nails In Process


Result ID Test Result Name Result LOINC Value
2535 Arsenic, Nails 8157-0
2509 Mercury, Nails 8204-0
2506 Lead, Nails 8202-4
PBNSC Specimen Source 31208-2
HGNSC Specimen Source 31208-2
ASNSC Specimen Source 31208-2


Nails grow at a rate of approximately 0.1 inch/month. Nail keratin synthesized today will grow to the distal end in approximately 6 months. Thus, a nail specimen collected at the distal end represents exposure of 6 months ago.



Nail arsenic above 1.0 mcg/g dry weight indicates excessive exposure. It is normal for some arsenic to be present in nails, as everybody is exposed to trace amounts of arsenic from the normal diet.


The highest hair or nail arsenic observed at Mayo Clinic was 210 mcg/g dry weight in a case of chronic exposure that was the cause of death.



Normally, nails contain less than 1 mcg/g of mercury; any amount above this indicates that exposure to more than normal amounts of mercury has occurred.



Normally, the nail lead content is below 4.0 mcg/g. Nail lead content above 10.0 mcg/g indicates significant lead exposure.


No significant cautionary statements

Method Description

Arsenic, mercury, and lead in nails are analyzed by inductively coupled plasma-mass spectrometry (ICP-MS) in kinetic energy discrimination (KED) mode using gallium, iridium, and lutetium as internal standards, and a salt matrix calibration.(Unpublished Mayo method)

Analytic Time

2 days

Specimen Retention Time

14 days

Clinical Information


Arsenic circulating in the blood will bind to protein by formation of a covalent complex with sulfhydryl groups of the amino acid cysteine. Keratin, the major structural protein in hair and nails, contains many cysteine residues and, therefore, is one of the major sites for accumulation of arsenic. Since arsenic has a high affinity for keratin, the concentration of arsenic in nails is higher than in other tissues.


Several weeks after exposure, transverse white striae, called Mees' lines, may appear in the fingernails



Once absorbed and circulating, mercury becomes bound to numerous proteins, including keratin. The concentration of mercury in nails correlates with the severity of clinical symptoms. If the nails can be segregated by length, such an exercise can be useful in identifying the time of exposure.



Nail analysis of lead can be used to corroborate blood analysis.

Test Classification

See Individual Test IDs