By Adele Visser

Introduction

Clinical cases often give us as health care providers the greatest opportunity to further our knowledge in parallel with providing essential treatment to our patients. This is true even for the seemingly common conditions that are encountered on a daily basis.

The aim of this newsletter is to provide a more targeted approach to the interpretation and therefore application of results in the management of patients.

Case Information

These are the results of a 62-year-old male patient. Very little clinical information as to his clinical presentation is available, however, it still enables some valuable consideration.

No follow up bloods or prior bloods are available, and the response is on a single sample.

 

Figure 1
Figure 1.

Essentials of results noted.

 

Case Discussion

There are certain essential issues which need to be addressed in this case:

I. Haemoglobin Level and Age
Patients over the age of 60 years are at increased risk of coronary artery insufficiency. They are therefore very dependent on an adequate amount of red cells to provide oxygen to the heart muscle. If the Hb is lower than 10g/dL, transfusion should be seriously considered.

For this reason, this patient will qualify for a blood transfusion, even if he does not clinically seem in distress.

II. Iron Studies and Transfusion
One unit of red cell concentrate (RCC) contains about 200 – 250mg of iron. Therefore, if the clinician performs a transfusion, and then only perform iron studies, the results will be irrelevant.

Iron studies should always precede transfusion.

III. Dimorphic blood picture noted
The dimorphic blood picture was very aptly noted by our technologist. Just to clarify, it refers specifically to the red cell line, and is noted when there seem to be two sets of cells, one big and one small.

There may be a couple of reasons for this. Firstly, it may be that there is also a vitamin B12 and/or folate deficiency which gives rise to a large set of red cells.

But more likely, the larger cells are reticulocytes. These are immature red cells that are pushed out of the bone marrow prematurely because the body is in dire need of more red cells.

In addition, the effects of this dimorphic picture can be seen in the raised red cell distribution width (RDW), which is a measure of the range of red cell sizes.

IV. Interpretation of iron studies
The serum iron represents the free iron that is present in blood – that which is freely available to your body to use. The portion that is bound, binds to transferrin.
The serum transferrin level therefore tells you how much binding protein is available – if there is very little iron, there will be a lot of transferrin floating around looking for iron to bind.
The % saturation represents this very ratio of iron to transferrin.
The serum ferritin represents the storage form of iron. Now, if the ferritin is low, this finding in itself is diagnostic of iron deficiency.

The problem with this test is that it is also an acute phase reactant – therefore, if a patient has any underlying inflammation, infection or physiological stress, the ferritin will go up, even if there is an iron deficiency.

The total iron binding capacity (TIBC) represents the body’s ‘greediness’ for more iron. Therefore, if the patient is iron deficient, the body will be very eager to get more iron, and this will manifest as a high TIBC.

 

Figure 1
In Summary.

 

Conclusions and putting it all together

When a patient, particularly adults, becomes iron deficient, it is almost always due to iron loss. Therefore, the question in cases of iron deficiency should always be, where is the patient loosing their blood/iron?

Women most frequently loose iron through menstrual losses, and for this reason we see iron deficiency almost exclusively in women. In men over the age of 60 years of age, blood (and therefore iron) loss through the gastro-intestinal tract accounts for most cases.

For this reason, iron deficiency in males over the age of 60 years is a very worrying finding as it is most commonly associated with colon cancer but may very well be more benign conditions like haemorrhoids. Therefore, this results should prompt further evaluation and/or testing depending on the clinical setting.