An NHS surgeon is advising people who experience unexplained tiredness and forgetfulness to request a specific blood test from their GP. Dr Karan Rajan highlighted that standard iron tests may not detect early deficiencies, as the first indicator is often a drop in 'storage iron' rather than iron in the blood.
Dr Rajan recommended checking ferritin levels, which provide the 'earliest and most sensitive' sign of declining iron reserves, even before anaemia develops. He explained that a full blood analysis should include transferrin saturation (TSAT) and total iron-binding capacity (TIBC) to assess usable iron and the body's iron absorption efforts.
The NHS ferritin test measures iron stores and is used to diagnose iron deficiency anaemia or conditions like haemochromatosis. Patients are usually asked to fast for 12 hours before the test. Low ferritin levels range from 12 to 30 ug/L, but symptoms such as pale skin, brittle nails, and hair thinning can appear below 70 ug/L.
Symptoms of low iron include tiredness, forgetfulness, low mood, pale complexion, and fragile nails. Less common signs may also occur. Treatment typically involves iron tablets, but Dr Rajan warned against supplementing without a diagnosis, as excess iron can cause constipation, nausea, and in severe cases, liver damage or heart failure.
NHS guidelines recommend daily iron intake of 8.7 mg for men and post-menopausal women, and 14.8 mg for women under 50 or menstruating. Iron-rich foods include red meat, pulses, nuts, dried fruit, and fortified cereals. Dr Rajan noted that iron supplements are best absorbed on an empty stomach, ideally in the morning.
