Cadmium Test

Cadmium is a heavy metal with no known benefit to human biology, but its toxic effects are well documented. It enters the body mostly through food, cigarette smoke, or inhalation of industrial dust or fumes—especially in jobs like welding, battery manufacturing, or smelting. Once inside, cadmium sticks around. Its biological half-life in the body is estimated to be 10 to 35 years, meaning it accumulates silently in tissues over time, especially in the kidneys, bones, and lungs.

In the kidneys, cadmium binds to a protective protein called metallothionein, which helps detoxify metals. This cadmium–protein complex travels through the bloodstream and is filtered by the kidneys, where it gets reabsorbed into the proximal tubule—a part of the kidney that normally reclaims nutrients and prevents protein loss in the urine. Over time, cadmium overwhelms the tubules, damaging them and leading to tubular proteinuria, or the leakage of small proteins like beta-2-microglobulin into the urine. This type of protein loss isn’t detectable on standard urine dipstick tests, but it’s a sensitive early sign of kidney stress.

As damage progresses, people may develop glucosuria (sugar in the urine despite normal blood sugar), phosphate loss, calcium loss in the urine, and difficulty concentrating urine, leading to frequent urination or dehydration. In severe cases, this can result in chronic kidney disease (CKD) or end-stage kidney disease (ESKD) requiring dialysis. Those most vulnerable include older adults, people with diabetes, and those with iron deficiency, which increases the absorption of cadmium from food.

Cadmium’s effect on bones is equally troubling. By interfering with the kidney’s ability to activate vitamin D, cadmium reduces calcium absorption from food, weakening bones and increasing the risk of osteoporosis and fractures. In the most extreme case—observed in Japan in the mid-20th century—cadmium-contaminated rice caused widespread osteomalacia, a painful softening of the bones, especially in older women. The condition became known as Itai-Itai disease, after the phrase “ouch-ouch” used by patients with severe bone pain and fractures.

Cadmium is also a carcinogen, meaning it’s known to cause cancer. Chronic exposure has been linked to lung cancer, especially in industrial workers, as well as prostate, testicular, and possibly kidney and bladder cancers. It causes oxidative stress, damaging DNA and interfering with repair mechanisms in cells. Inhalation of cadmium fumes can also lead to chemical pneumonitis, a severe lung inflammation that can progress to acute respiratory distress syndrome (ARDS), a life-threatening condition where fluid fills the lungs.

Other potential effects include immune suppression, nerve problems like memory loss or Parkinson-like symptoms, reproductive harm (especially in the testes), and even vision problems such as cataracts and macular degeneration. In people with chronic exposure, symptoms may be mild or nonexistent for years, making early detection difficult.

There’s no reliable treatment for chronic cadmium poisoning. The main strategy is eliminating further exposure—quitting smoking, using protective equipment at work, and reducing intake of contaminated foods (particularly rice from polluted areas). Chelation therapy—a treatment that binds metals to help remove them—is not recommended for long-term cadmium exposure and may worsen kidney damage. In acute cases, such as industrial accidents, a chelator called succimer may help if given early.