Iron Blood Test Tips

34% of menstruating females are seen as deficient in iron

Iron supplements Stop for 3 days before a blood test otherwise it will elevate Transferrin saturation levels and give a false ferritin surplus reading.

Alcohol Avoid the night before as alcohol increases iron availability and gives a false high reading

Strenuous exercise Avoid for 2 days prior to a blood test as this increases inflammation so CRP will rise and iron absorption will drop.

Fasting You need to fast for 5 to 12 hours before blood is taken [ideally 9-10 hours]

Iron is an essential mineral but dangerous to the body in large amounts. The body will prevent iron absorption if there is a bacterial infection. Bacterial infections create inflammation which triggers the body to stop iron absorption so if the body detects inflammation it will assume there is a bacterial infection and stop iron absorption e.g. from strenuous exercise, injury. Iron will be moved out of the blood and stored in the liver. Serum iron drops, transferrin saturation drops and ferritin slightly rises because iron is being hidden in the liver.

Serum iron is the least meaningful and least reliable element to measure. Very fickle, moves up and down at different times of day and food intake and drops dramatically when there is inflammation

Haemaglobin reference range only gives a minimum of > 120 (less for Asian and African American women). There is no maximum level but higher is not better! It is very common for menstruating women to have 120-130 and only shift up at menopause. Higher levels are associated with higher mortality 

Transferrin is the taxi for iron [i.e. a marker of shortfall or hunger for iron]

Transferrin is the bodies first response to that individuals shortfall. When a persons is not quite meeting their needs for iron the body responds making the liver produce more transferrin. It is the bodies way of saying I need more iron ie liver sends out more transferrin taxis to pick up more passengers [iron] from the gut.

However this is not true when the body is inflamed by infections, excessive exercise, injuries we can’t say higher transferrin levels mean that you are in need of iron as at this stage the body is stopping absorption and storing away iron in the liver instead.

Pregnancy It is extremely important to have high transferrin to give iron to foetus > 300 – 500

Oestrogens from HRT or contraceptive pill trick the body into thinking there is a baby on board and more iron is needed. So transferrin up regulates so it is now not an indicator that this woman is not meeting her iron needs.

Obese individuals carry an inflammatory load. Transferrin is not an indicator of iron shortfall or iron hunger in obese patients. It is an indicator of iron regulation irregularity.

Transferrin will be quite high although the ferritin is already high. 

Transferrin saturation % is bums on seats ie what % of seats are occupied by iron. 

Transferrin saturation at high levels is possibly iron dumping. Delivering excess of what is needed to organs and tissues or joints, endocrine glands and brain.

Common % Transferrin saturation in menstruating female is 20-25% [seats occupied in the taxi] 30% in men > 45% is too high and may predispose them to haemachromatosis.

35% in woman is not common and if seen consistantly in a fasting state then maybe danger of haemachromatosis (iron overload). Beware of inexplicable joint pain. Iron is commonly dumped in joints.

Ferritin 20-220 is official range but 34-46 is the average ie ideal for menstruating women. Ferritin is a surplus so we don’t want more surplus so don’t go for higher levels.

If you are feeling well, not overly tired, short of breath, dizzy then you are at your ideal ferritin level. Your sweet spot may be only 25 as long as your  Transferrin saturation % is not high so therefore not demanding more uptake.

Someone elses Transferrin saturation % may be 30 or 40 showing a hunger for more iron so this individual needs more.


Taking large doses ie > 20 mg elemental iron is too high a risk for the body. So the gut reduces absorption. 70-90 mg per day will create a shutdown for 48 hours.

Taking 20 mg of iron every 2nd day re Monday, Wednesday, Friday is proven to be the most effective.

Vegans have no excess iron so can have a daily 20 mg dose.

Joint pain consider possible inflammatory causes such as;

Excess exercise
Bacterial and other infections
Excess iron [stop supplementation]

Signs & Symptoms of mild iron deficiency [supplements may help;
Fatigue, tired, exhausted

Signs & Symptoms in severe iron deficiency [iron infusion needed]
Severe chest pain
Air hunger, can’t get air into their lungs e.g. at top of stairs
Feel faint, need to sit down
Mummy brain, forgetfulness, brain fog
Withdrawn, depression, anxiety
Muscle cramps
Restless legs at night
Pica – Desire to eat strange foodstuffs e.g. ice, soil, plaster, smell of rubber [24 hour cure after infusion of iron]

Causes of iron loss;
Pregnancy, blood loss e.g birth, caesarian
Heavy periods
Vegetarianism especially teen females
IBD reduces absorption and blood loss

Endurance athletes.  Iron is lost when sweating as iron is concentrated in the skin at 10x blood levels. Also exercise may promote inflammation which reduces the bodies ability to absorb iron.

1/3 to 1/4 of women are iron deficient
The most common reason for iron deficiency in women is heavy menstrual bleeding.

Heavy bleeding may manifest as;
Do you need to double protect?
Do you need to get up at night time to change your protection?
Do you need to change more than 12-14 times in a cycle?
Do you have fear of flooding or accidents 

There are two pathways for the body to absorb iron
1. Haem pathway – Iron in meat is haem iron
2. General mineral pathway where iron, zinc, magnesium etc gets absorbed very inefficiently

Iron eaten in food
HCL acid in the stomach breaks down and separates the iron from food. Iron  is then absorbed in the duodenum.
Enterocytes are the gut cells where the iron is stored.
Ferroportin will move the iron out of the enterocytes if you are low in iron.
Transferrin will move this iron into the blood and into the red blood cells.
Ferritin inside the red blood cells stores the iron.
Hepsidin tells the enterocytes to stop ferroportin moving iron into the blood when the ferritin levels are high. Therefore iron can still get into the enterocytes cells but can’t get out into the blood.

Ferretin at 50 is an adequate iron storage level so taking iron when you are at 50 will not increase your ferritin
Ferritin at 30-50 is when the ability to absorb iron increases. Meat, lentils, pulses and soya will supply your needs.
Ferritin < 30 is when you may need to supplement
Ferritin < 15 is when a blood Infusion is needed

Green leafy vegetables are totally useless as a source of iron as iron is too tightly bound to the food.

Your body can only absorb 6-8 mg of elemental iron per day so one tablet is enough.  Taking 2 will not increase iron as it can not be absorbed. The iron absorption will be blocked for the next 24-36 hours.

Taking one iron tablet every 2nd day is as good as having one every day.

More iron tablets will just make the enterocyte slough off  causing local toxicity with symptoms such as constipation, diarrhoea and stomach ache.

Spare Iron is also stored in ferritin in the liver as a reserve store of aprox 1,000 mg iron. If you lost all of your blood you will have enough stores to build up your blood again. Another 1,000 mg of iron is found in the muscle and every other cell in the body, particularly in nervous tissue as it is important for metabolism.

When you breathe the red cells go to the lungs, pull out the oxygen and delivers oxygen to every cell of the body. Oxygen and glucose is converted to energy via the ATP cycle. All the steps and enzymes to produce ATP need iron.

If you are very low in iron your aerobic metabolism does not work properly which affects every cell in the body and particularly the brain where oxygen and glucose is vitally important. Therefore you can get fatigue, brain fog, inability to think clearly, muscle twitching and cramping.

In pregnancy the foetus can be supplied by iron stores in the mothers liver which can may make her feel unwell. If iron stores are low then the mother must take iron out of the muscles and nervous tissue which means that the mother can be iron deficient long before their blood iron is low [anaemia] in a blood test.

Insufficient iron in pregnancy can increase the risk of premature labour, intrauterine growth retardation, perinatal and maternal mortality, and postpartum depression. 15 mg/day of iron bisglycinate is more effective at preventing pregnancy-related iron depletion than 40 mg/day from iron sulphate with fewer undesirable effects such as constipation. It is important to choose an iron supplement with highly bioavailable iron, activated B12 and 5-MTHF, vitamins C and B6 to ensure energy production. Unlike B12 found in food, supplemental activated B12, is not bound to a protein, therefore absorption is not impaired by low stomach acidity [see digestion; Low stomach HCL] which can reduce B12 uptake from dietary sources. A deficiency of vitamin B12 and/or folate can result in large, immature and dysfunctional red blood cells.