Total Iron Binding Capacity (TIBC) Lab Values

Hey everyone. Abby here with NURSING.com. Today, we’ll discuss a lab value called total iron binding capacity. The abbreviation is TIBC. Let’s get started!

Total iron binding capacity measures the blood’s ability to attach and transport iron around the body. Iron attaches to the red blood cells via transport proteins and is delivered to the bone marrow so that iron can help boost healthy red blood cell production. Now, can you think of a time when there might be a lack of red blood cell production and what type of clinical picture we might be seeing with that? I bet you’re thinking anemia and you’d be right! With patients that are anemic, they may be fatigued, dizzy, weak, present with headaches, or even have pale skin. This lab would be indicated in that case. We need to know if iron is able to be transported to the bone marrow. We want to know the total iron binding capacity. Now, it’s also indicated if iron overload is suspected. This might be someone with liver disease as iron can actually cause organ damage, or in iron supplement poisoning, say a child got into a bottle of supplements and ended up taking all of them.

I saw the TIBC taken as part of lab studies of, uh, ferritin as well as other iron evaluations in bone marrow transplant patients, because iron is so essential to the bone marrow to produce red blood cells at a bone marrow transplant has hopefully been engrafted and received that transplant, it’s used to determine if it’s functioning properly. Normal therapeutic values are between 250 and 460 micrograms per deciliter. Collection of this specimen takes place in a serum separator tube, or a gold top. Lab values can be a little bit confusing so, let’s talk about it. So, before I go into increased and decreased, let’s just take a look at the relationship. Total iron binding capacity measures the ability for iron to attach to transport proteins. So, let’s look at increased first. If the TIBC is elevated, that could mean that there’s a low amount of iron in the blood, because if there’s not as much iron in the blood, that would mean that there are more binding sites available right? Right.

Now, if it’s decreased, the same would be true. If there is a low number of transport proteins, or if there’s a lot of iron that’s going to change this relationship, they’re totally inverse. So, if you have a lot of iron in the body, you have fewer transport sites, right? But, it could also be just in terms of the transport proteins that are available. It can also be decreased in inflammatory states and also in liver disease. 

The linchpins for this lesson remember, are the total iron binding capacity is actually measuring the amount of binding sites available from those transport proteins on the red blood cell. The normal value is between 250 and 460 micrograms per deciliter. Very important to remember, if iron stores are low, we’re going to have more binding capacity, right? So, they have that inverse relationship rather. Whereas if iron stores are high and taking up those binding sites, or if those transport proteins are not available, then the total iron binding capacity will be low. You can do this! Remember, we love you guys. We’re here to help you succeed, now go out and be your best self today, and as always, happy nursing!

References:

• https://www.mayoclinic.org/tests-procedures/ferritin-test/about/pac-20384928
• https://www.uptodate.com/contents/image?imageKey=HEME%2F76236&topicKey=HEME%2F7150&search=TIBC&source=see_link
• https://www.uptodate.com/contents/causes-and-diagnosis-of-iron-deficiency-and-iron-deficiency-anemia-in-adults?
• https://www.uptodate.com/contents/regulation-of-iron-balance?search=TIBC&source=search_result&selectedTitle=2~137&usage_type=default&display_rank=2
• https://www.uptodate.com/contents/diagnosis-of-iron-deficiency-in-chronic-kidney-disease?search=normal%20TIBC%20lab%20lvalue&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1
• https://www.ncbi.nlm.nih.gov/books/NBK559119/
• https://www.labcorp.com/help/patient-test-info/transferrin-and-iron-binding-capacity-tibc-uibc