The lead test is used to evaluate the concentration of lead in your blood to determine if you have been exposed to harmful levels.

Blood lead is monitored in workers whose environment contains lead. In Australia the main sources of lead exposure are air-borne lead (from industrial sources and from the use of lead in petrol), and occupational and hobby exposure (e.g. plumbers and stained glass artists).

For screening: Blood lead tests may be ordered to screen people in the workplace if lead contamination is a potential problem. This testing conforms to Health and Safety Executive rules for occupational exposure.
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. For a list of hobbies that may expose you to potentially high levels of lead, go to lead poisoning.

The NHMRC guidelines for blood lead concentration indicates that the normal blood lead concentration is less than 5.0µg/dL (0.24µmol/L).
 

Workplace exposure
Blood lead levels in workers vary depending on whether the worker is male or female and how high previous levels were. These are laid out in this Safe Work  Australia document.

For diagnosis: The test can help determine whether symptoms, including fatigue, changes in mood, nausea, headache, tremors, weight loss, or decreased libido, are due to lead poisoning. The test may also be needed if a patient has peripheral neuropathy, anaemia, reproductive failure, encephalopathy, or memory loss, which are symptoms of lead poisoning.

The higher the test result, the more lead is in your system and the more potential danger there is to your health. Guidelines and recommendations for treatment differ for children and adults.

Most experts agree that at a very high blood lead concentration, above 70 - 80 µg/dL (3.5-4.0µmol/L) a person is at the medical emergency level and should get immediate medical attention. This may include chelation therapy if the blood levels are very high. Abatement - removing the source of the environmental exposure to lead - must also be done. Most also agree that adults with blood concentrations of less than 10 µg/dL (0.5 µmol/L) are not lead poisoned, and further testing is not necessary unless they are exposed again.

Children are more susceptible to lead poisoning than adults and current standards indicate that lead levels in children should not exceed 5 µg/dL (0.24 µmol/L). 

Any child who has an elevated blood lead level needs to have their home or other environment evaluated. Other people at the residence should be tested as well. Without treatment or abatement of the environmental cause, the elevated lead level will probably recur. 

Poisoning with lead is more harmful for children, whose brains and other organs are still developing. Adults tend to recover from lead ingestion better than children. If you think your children may be at risk, have them tested as soon as possible.

Iron deficiency can make lead easier to absorb in the body. Children with raised blood lead concentrations should have testing for iron deficiency.

Each person handles lead differently. What may be toxic to one adult may not be toxic to another. Thus, laboratory tests are just one part of the picture in lead poisoning cases. Careful monitoring with medical examinations are needed.

Products that still contain lead include batteries, solder, some pipes, ammunition, roofing, industrial paints, and X-ray shield materials.

Just holding a lead object in your hands won't poison you. Breathing in or swallowing lead may poison you, however. Some examples of lead poisoning situations would be:

• inhaling dust from a home renovation project on an old house;
• swallowing lead shot (for a shotgun), a curtain weight, or a lead toy and not passing it through your system; and
• inhaling burning lead-painted wood or battery casings in home fireplaces.

Occupations that put people and their families at risk for lead exposure include:

• lead mining and smelting,
• construction,
• steel welding,
• bridge reconstruction,
• firing range instructors and cleaners,
• remodelling and renovating old houses,
• foundry work,
• scrap metal and battery recycling,
• car repair,
• cable splicing.
• battery, glass and ceramic ware manufacturer.

Yes. If you are working in a potentially harmful environment with exposure to lead dust or mist: 

• wash your hands before you eat, drink, or smoke; 
• eat, drink, and smoke in areas that are free from lead dust and fumes;
• wear a properly fitted respirator with a HEPA filter. Shave your face to get the best fit;
• keep your street clothes in a clean place. Change into different clothes and shoes before you work with lead;
• shower immediately after working with lead, before you go home; and 
• launder your work clothes at the work place or separately from other family members' clothes.

For more information about lead poisoning and workplace safety, visit the Safe Work Australia website.