Low iron causing anaemia

Clinically: Iron deficiency anaemia · also iron deficiency, IDA, low iron, not enough iron, too little iron, anemia from low iron

hematologic ICD-10 D50.9 MONDO MONDO:0001356 unverified

This describes what this condition typically looks like. It is not a diagnosis and cannot tell you whether you have it -- patterns overlap, results vary between labs, and the same numbers mean different things in different people. Diagnosis usually rests on Ferritin, Hemoglobin, interpreted alongside symptoms and history rather than read off a report. Note that a normal-looking result does not reliably rule this out -- see the caveats above.

unverified These explanations are written to be easy to read and have not yet been checked against a source. The ranges and measurement notes on this page show theirs.

definition unverified

Your body has run low on iron, and it no longer has enough to build healthy red blood cells. Because red cells carry oxygen, everything starts to feel harder than it should.

Anaemia resulting from depleted iron stores insufficient to sustain erythropoiesis, classically microcytic and hypochromic.

why measured unverified

It is common. A blood test confirms it easily. And it is usually simple to put right, once you know why it happened.

No clinical version written yet.

caveats unverified

Ferritin rises whenever there is inflammation anywhere in the body, so a result that looks normal can still hide a real shortage. This is why an inflammation marker is usually checked alongside it. Finding low iron is only half the job -- the more important question is why it went low.

No clinical version written yet.

How common it is

The most common nutritional deficiency worldwide. Considerably more common in women who menstruate, in pregnancy, and in anyone with ongoing blood loss.

The typical lab pattern

What the diagnosis rests on

The results a diagnosis is actually made on.

Ferritin	low	—	The key test for confirming iron deficiency. Below 15 µg/L means iron stores are empty, and is almost never seen without iron deficiency. Inflammation can make ferritin look normal.
Hemoglobin	low	—	Anaemia is defined as haemoglobin below the lower limit of normal. Iron stores can run low while haemoglobin is still normal.

Consistent with it

Fits the picture, but not enough on its own.

Iron saturation	low	—	Low in iron deficiency. Mainly useful when ferritin may be falsely normal, such as during inflammation.
Mean corpuscular volume	low	—	Red cells get smaller (microcytosis), but thalassaemia and some other anaemias do this too.
Erythrocyte distribution width	high	—	Can rise early in iron deficiency, before the MCV falls.
Iron, serum	low	—	Often low, but blood iron varies through the day (it may be higher in the morning), so it is weak on its own.
C-reactive protein	either	—	Checked alongside ferritin. Ferritin rises with inflammation, so with a raised CRP a normal ferritin may hide iron deficiency.

How it usually feels

Feeling tired all the time · common
Getting out of breath easily · common
Hair thinning or falling out · occasional
Looking unusually pale · common
Spoon-shaped nails · rare
Trouble thinking clearly · occasional

Frequencies say how often a symptom accompanies this condition — not the other way round. Most people with any of these symptoms do not have this.