PROTEINOGRAM: WHAT IT IS FOR, INTERPRETATION AND VALUES - ANATOMY AND PHYSIOLOGY - 2025

The proteinogram, a simple way of calling serum protein electrophoresis, is a semi-quantitative method that analyzes proteins in the blood, a test frequently requested by physicians. Serum proteins are substances made up of chains of amino acids that perform different functions in the body.

The most important functions of these proteins are the transport of certain elements that are present in the blood and some defensive tasks. The proteinogram provides valuable information regarding the internal conditions of the body.

Alterations in its results can be associated with different clinical entities and even guide the doctor towards the best available treatment.

How it is performed?

In the past, filters made of paper, agarose or cellulose acetate were used to separate the proteins from the other elements of the serum.

They were then stained with different dyes and quantified through a densitometer. Today some of these methods are preserved but with substantial improvements.

Proteins possess negative or positive electrical charges and move in flux when placed in an electric field.

Capillary electrophoresis, the most widely used mechanism today, uses these fields to separate proteins and group them according to their electroosmotic charge, size and shape, allowing a faster, more precise and comfortable study.

What is it for?

Protein electrophoresis is performed primarily to aid in the diagnosis and management of certain diseases. Among the large number of medical conditions that can modify the levels and characteristics of serum proteins, the following stand out:

- Some forms of cancer.

- Liver or kidney disorders.

- Alterations of the immune system.

- Malnutrition.

- Infections.

Normal values

Serum protein levels may vary slightly depending on the laboratory where the studies are performed, the type of equipment used and the reagents.

Despite this, there are ranges considered normal and the reference values ​​are included in the printing of the results, which should only be interpreted by the doctor.

Albumin

3.3 - 5.7 gr / dL

Alpha 1 globulin

0.1 - 0.2 gr / dL

Alpha 2 globulin

0.6 - 1 gr / dL

Beta globulin

0.7 - 1.4 gr / dL

Gamma globulin

0.7 - 1.6 gr / dL

Some laboratories change the reporting units to grams per liter (gr / L) for which only the comma should be rolled one space to the right. For example, albumin: 33 - 57 gr / L. The same applies to the rest of the proteins and globulins.

Interpretation

Isolated alterations in serum protein levels are rare, with several being altered at the same time.

However, each one of the proteins is reported separately below with the possible causes of alteration to later make an analysis by pathology.

High albumin

Dehydration and some immune diseases.

Low albumin

Malnutrition, kidney or liver failure and inflammatory processes.

Alpha 1 globulin high

Infectious and inflammatory processes.

Low alpha 1 globulin

Severe inflammation and liver disease.

Alpha 2 globulin high

Inflammatory processes and kidney disease.

Low alpha 2 globulin

Thyroid and liver problems.

High beta globulin

Severe hyperlipidemias and iron deficiency anemias.

Low beta globulin

Malnutrition and immune diseases.

High gamma globulin

Bacterial infections, sepsis, some types of cancer, and chronic liver disease.

Low gamma globulin

Innate Immune Disorders.

Diseases that can modify the result

As mentioned previously, there are many diseases that can modify the results of the proteinogram. Some of them are mentioned below, with the behavior of serum proteins in each of these.

Hepatic cirrhosis

It is characterized by the decrease of all serum proteins synthesized in the liver, especially albumin, whose level decreases alarmingly. There may also be a reactive elevation of immunoglobulins.

A striking fact is the virtual elevation of some globulins; These, as they are not metabolized due to liver disease, remain in the body longer without this representing a true increase in their value.

Nephrotic syndrome

It also causes significant hypoalbuminemia because the kidney does not adequately filter proteins. Lower molecular weight proteins are usually lost in the urine and higher molecular weight proteins rise in the blood as compensation.

Inflammation

There are different patterns for acute inflammation and for chronic inflammation. In acute inflammation, there is an elevation of alpha-globulins, both 1 and 2, which behave as acute phase reactants. A slight decrease in other globulins can also be found due to a compensatory effect.

In chronic inflammation, albumin is already compromised, so its level begins to decrease. This phenomenon can be accompanied by an elevation of gamma globulin as long as there are no immunological disorders.

Pregnancy

Despite not being a disease itself, pregnancy produces important anatomical and physiological changes in women, with serum protein levels not escaping.

Albumin values ​​are slightly low due to hemodilution (increased fluid in the blood vessels). Due to the action of the hormones of pregnancy, such as estrogens, globulins and transferrin rise.

Monoclonal gammopathy

Gamma globulinopathies are the most common innate immunological diseases among the group that affects serum proteins. They are characterized by the presence of recurrent infections and a deficit in weight-bearing development.

A significant decrease in gamma globulin is usually found in the proteinogram, accompanied by a compensatory elevation of beta and alpha globulins.

"Immature" forms of gamma globulin also appear, which is very helpful in making the diagnosis, since it is a pathognomonic phenomenon of this condition.

Detailed analysis required

Serum protein electrophoresis is an extremely useful laboratory study for the detection and management of many chronic infectious, immunological and oncological diseases, among others. It is a method with considerable clinical sensitivity from the biochemical point of view but with low specificity.

It is important to understand that different clinical events produce different alterations in the pattern of the proteinogram and almost none of these modifications is specific for a disease, with the exception of some type of gamma globulinopathy, for which a detailed analysis by the specialist doctor is essential to the correct diagnosis.

References

1. Abraham; Barnidge and Lanza (2013). Assessment of proteins of the immune system. Clinical Immunology, Fourth Edition, Chapter 93, 1145-1159.
2. Poinier; Gabica; Thompson and Husney (2017). Serum Protein Electrophoresis (SPEP). Health library. Test overview.
3. Cidoncha Gallego, A. et al. (2001). The proteinogram in clinical practice. Integral Medicine, 38 (3), 127-132.
4. Dasgupta, Amitava and Wahed, Amer (2014). Protein Electrophoresis and Immunofixation. Clinical Chemistry, Immunology and Laboratory Quality Control, Chapter 22, 391-406.
5. O'connell, Theodore and Horita, Timothy and Kasravi, Barsam (2005). Understanding and Interpreting Serum Protein Electrophoresis. American Family Physician, 71 (1), 105-112.
6. Wikipedia (latest edition 2017). Serum Protein Electrophoresis. Recovered from en.wikipedia.org.