robinhy--Welcome to the boards!
I will try to answer your questions.
Ferritin is an iron storage protein that the body synthesizes, FREE iron can be toxic to our organs. To prevent iron toxicity the body regulates the level of ferritin (synthesis) to accommodate different levels of iron. Ferritin is stored in the bone marrow and organs. Ferritin is used (called on) when the need for iron intake increases to build the Hgb so that you do not become anemic. When the iron stores are depleted, iron is then pulled from the organs, this is a more dangerous stage.
When your total body iron is high ferritin is usually high, when total iron body is low, ferritin tends to be low as well. ~Iron deficient people~ tend to have a ferritin less than 10 whatever the bottom of your range is. My Hematologist says under 10, there is no iron remaining.
Ferritin can also be confusing in the presence of inflammation as you mentioned, because it is an ~acute phase reactant~, and can also be elevated in the presence of an iron deficiency anemia
. For example, i.e., if you have an infection
with iron deficiency anemia you can be iron deficient with a very high ferritin.
The end stage of the ferritin stores is IDA iron deficiency anemia. So until the iron stored are used up you will not become anemic. Anemia MAY not show until your ferritin is 5 or below around this range anyway. It is different for each person.
Yes, inflammation/infection can give a false ferritin level. This reading would be different for each person I have not read a certain level anywhere. I know it is elevated in different settings so who knows how high it can go. My husband had a 3,000. ferritin for a different reason. So typically ferritin will rise depending on the cause. You can also seek further testing regarding inflammation to see how high it is elevated in your body. A simple blood test CRP and SED rate will give you these answers. Perhaps you have also had this testing as well. But it will show inflammation.
With that being said, the Iron study gives the amount of iron in circulation in the body at the time of blood testing. For example from what you eat, supplements, a total iron intake, the iron serum reflect this. So, if you have recently eaten iron rich foods, like steak, or taken iron supplements it will show in the iron serum. If you took iron and had a blood test it could skew the results.
Doctors rely on the ferritin for sure!!!! If it is not high over range they don't care, if it is too low but within range they don't care too much either. And....if it is a little low below range but you are not anemic yet, they still don't care too much. It is up to you unfortunately to know what is happening. I know my Hematologist said, anything under ten and over one thousand he is concerned, because that is when you to store too much iron and overload. And...under the 10 mark you become anemic.
Ferritin is more telling of the stored iron in the body and can be falsely elevated. Iron studies tell about the iron in circulation in the bloodstream. Excess iron that is not used is then stored. So, if you are not taking in enough iron you will be using stored iron. If there is blood loss there is iron loss. This will deplete your stores over a period of time. Any blood loss = iron loss. Malabsorption also results in iron loss and other nutrients.
Have you had your B-12 tested? It can cause several of the symptoms that you mention, as can iron and thyroid. And could possibly be a result of Crohn's disease.
Thyroid can also cause heavy periods and less stomach acid resulting in less iron absorption. Many people that are Hypo-T also have a low ferritin it is very common.
Symptoms of Thyroid, Anemia and low ferritin can be very much alike. It is hard to tell what is happening you have to reply on blood tests for this and how well you respond to therapy. When you have multiple problems it is best to work on one at a time and rule out each possible thing that is happening. It can be a daunting task but it does work. I would start by taking the right amount of iron that is needed and do whatever it is that your doctor recommends regarding your thyroid. You can be in range and have a great deal of problems. If you require meds then try to take them. I know it can be hard. You can have more problems in the end if you do not supplement thyroid hormone if it is needed.
Hope that helped a little. Take care and keep us posted. FLFLOWERGIRL