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PTD - 256

Test Directory -  Lead

Clinical Indications

Lead poisoning is a preventable condition that results from environmental exposure to lead. This exposure can result in permanent health damage, especially among children.In the UK the main sources of lead exposure are air-borne lead (from industrial sources and from the use of lead in petrol), water-borne lead (where lead dissolves readily from lead piping or from lead solder in water pipes, sometimes found in pre-1970s buildings), and occupational and hobby exposure (e.g. plumbers and stained glass artists).

Lead poisoning can affect almost all parts of the body, including the central nervous system, kidneys, and reproductive organs. It commonly causes weakness and abdominal discomfort and less often causes abdominal pain, vomiting, constipation, foot and wrist drop and anaemia. In children especially, it impairs cognitive development, which can lead to learning disabilities and behavioural problems. At very high levels, it can even result in hallucinations, coma, seizures, and death.

Screening: Adults who work in industries known for lead exposure, for example plumbers, lead miners, shipbuilders, construction workers, demolition workers and pottery manufacturers should be screened for lead exposure. Adults who have hobbies that involve lead-based paints, ceramics, soldering etc should also be tested.

Diagnosis: Symptoms, including fatigue, changes in mood, nausea, headache, tremors, weight loss, or decreased libido, may be due to lead poisoning. The test may also be useful in investigation of patients for peripheral neuropathy, anaemia, reproductive failure, encephalopathy, or memory loss, which are symptoms of lead poisoning.

Request Form

Combined Pathology Blood form (Yellow/Black)

Availability

Referred test: Analysed by Clinical Biochemistry, Kings Hospital, if specific criteria met.

Specific Criteria

Occupational Health screening of workers at risk from lead exposure. Investigation of symptomatic patients.

Patient Preparation

No specific preparation required

Turnaround Time

2 weeks

Volume

5-10 ml (paediatric 2-5 ml)

Specimen

Pink / purple top (EDTA) or

Red top (EDTA) tube for paediatrics.

Causes for Rejection

Unlabelled sample. Not meeting specific criteria for analysis.

Reference Range

Less than 0.5 umol/L

Occupational monitoring

When employees are significantly exposed to ionic lead compounds, their blood lead levels should be measured every three months. If exposure is uniform, then a consistent blood lead pattern will probably be established, although this may take about a year. Thereafter, except for women of reproductive capacity and young persons, blood lead measurements can be taken at the reduced intervals shown in the table below.

Blood Lead (µg/dL) Maximum interval between blood lead measurements
under 30 12 months (see note below)
> 30 < 40 6 months
> 40 < 50 3 months
> 50 < 60 3 months
60 and over at the doctor’s discretion but not more than 3 months

Unit Conversion

To convert from umol/L to ug/dL multiply by 20.7

Lab. Handling

Processing: DO NOT SEPARATE SAMPLE. Store whole blood at 4°C in separating fridge (CB39).
Referral
: PB and send or BPRO and save whole blood at 4°C in the cold room (CB23).

         

 


Version 1.0 / July 2014                                                                                                            Approved by: Consultant Biochemist