Lead (blood)

There is no level of lead the body needs; UK labs print an upper limit for the general population of about 0.24 umol/L (5 ug/dL, some print 0.48), a lower figure for children and pregnancy, and separate higher action levels for people exposed at work under health and safety law.

Lead is a metal with no role in the body; it is measured because it can build up from old paint, old water pipes, some traditional remedies and cosmetics, hobbies such as shooting or stained glass, and some jobs. The blood test measures lead in whole blood, most of it inside red cells, and reflects exposure over the past few weeks to months. Lead affects the blood, the nerves, the kidneys and, in children, development.

It is requested when exposure is possible, in children who have swallowed paint or soil, in people working with lead under health and safety monitoring, in people using traditional Ayurvedic or other remedies, and when unexplained anaemia, tummy pain, nerve problems or high blood pressure are being looked into. It is sometimes checked in pregnancy where exposure is possible.

• Work with lead: battery recycling, demolition, painting old buildings, plumbing, shooting ranges
• Old lead paint and old lead water pipes, especially in children
• Some traditional remedies, imported cosmetics (kohl, surma) and glazed pottery
• Hobbies: shooting, fishing weights, stained glass, restoring old cars
• Living near a smelter or on contaminated land
• Release from bone stores in pregnancy, breastfeeding, the menopause and with bone loss

• Ending the exposure, after which the blood level falls over weeks to months while bone stores clear over years
• A value below the cut-off is the expected finding
• Chelation treatment, in a hospital setting

• A low positive value is common in the general population, particularly in older people who grew up with leaded petrol and paint
• Blood collected in a standard tube rather than a trace-element tube can be contaminated
• A skin puncture sample in a child can be contaminated by lead on the skin

A whole blood EDTA sample in a trace-element tube, no fasting needed. Repeat testing is used to follow a raised value once the source has been found and removed.

Written by a UK consultant physician. Typical UK adult reference ranges; your laboratory's own printed range takes precedence.