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Test Code MISC2MAYOHMNA 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

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Nail


Necessary Information


Indicate source of nails (fingernails or toenails), if known



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.


Specimen Minimum Volume

0.05 g

Specimen Stability Information

Specimen Type Temperature Time Special Container
Nail Ambient (preferred)
  Frozen 
  Refrigerated 

Reference Values

ARSENIC

0-15 years: not established

≥16 years: <1.0 mcg/g of nails

 

LEAD

<4.0 mcg/g of nails

Reference values apply to all ages.

 

MERCURY

0-15 years: not established

≥16 years: <1.0 mcg/g of nails

Day(s) Performed

Tuesday

Test Classification

This test was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

82175-Arsenic

83655-Lead

83825-Mercury

LOINC Code Information

Test ID Test Order Name Order LOINC Value
HMNA Heavy Metals, Nails 94574-1

 

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

Clinical Information

Arsenic

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

 

Mercury

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 may be useful in identifying the time of exposure.

 

Lead

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

Interpretation

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.

 

ARSENIC

Nail arsenic above 1.0 mcg/g dry weight may indicate 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, which was the cause of death.

 

MERCURY

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

 

LEAD

Normally, the nail lead content is below 4.0 mcg/g. While nail lead content above 10.0 mcg/g may indicate significant lead exposure, nails are also subject to potential external contamination with environmental lead. Ultimately, the nail lead content needs to be interpreted in addition to the overall clinical scenario including symptoms, physical findings, and other diagnostic results when determining further actions.

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)

Report Available

2 to 8 days

Reject Due To

All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Method Name

Inductively Coupled Plasma-Mass Spectrometry (ICP-MS)

Secondary ID

31070