Total protein

Your blood plasma is a small part protein, and that small part does a lot: it keeps fluid in your vessels, carries substances, clots your blood and defends you against infections. Total protein is the sum of all those proteins. Roughly sixty percent is albumin, one protein your liver makes. The remaining forty percent are the globulins, a group with your antibodies from the immune cells, the transport proteins for iron, copper and hormones, and the clotting factors. Because it is a sum, the number itself does not say which protein has changed. Two people with the same total can have a very different distribution. That is why total protein rarely stands alone on a report: albumin beside it, and the difference between the two, the globulin, carry the meaning. If the total rises while albumin stays the same, the rise sits in the globulins, usually in the antibodies. If they fall together, it is less production, more loss or dilution. Your report shows total protein in g/L. Normal is about 63 to 81 g/L, with limits that shift by a few units per lab. It is a concentration, so thickened blood gives a higher number and a large blood volume a lower one, without protein being added or lost.

Total protein is rarely the value you read something from, and often the value that asks the question. In anyone healthy it mainly moves with fluid: too little drunk gives a higher number, drinking a lot or a large blood volume from endurance training a lower one. That is the first question with every deviation, and usually the answer. The second question is the distribution, and that is where it gets interesting. A total protein that rises while albumin stays the same or falls means more globulin, and that is usually more antibodies: with a long-standing inflammation or infection, with a liver disease in which the immune system works harder, or rarely with a proliferation of one kind of antibody cell that makes one protein in large amounts. That last one is the reason a persistently high total protein with a normal albumin is split out with a protein electrophoresis. A total protein that falls while albumin falls with it is the liver making less, kidneys letting protein through, or too little protein in the diet. The third reason is diet. Anyone who eats too little protein for a long time sees first albumin and then the total fall. A total protein at the low end in someone dieting, with little appetite or getting older, is the question of whether there is enough protein on the plate, and the answer is protein at every meal.

A low total protein means dilution, less production, more loss or too little supply. From common to rare: dilution by fluid, a liver making less, protein loss through the kidneys, and taking in or absorbing too little protein. Look at albumin: if that falls with it, it sits in the production, the loss or the diet, and CRP, the liver values and protein in the urine say which. If albumin stays the same, the fall sits in the globulins, and that is rare. A high total protein means thickened blood or more globulin. Dehydration is the most common reason; drink normally and have blood drawn again. If it stays high while albumin stays the same, the rise sits in the antibodies: a long-standing inflammation or infection, or rarely an abnormal protein from one cell line, and then a protein electrophoresis follows. Set total protein beside albumin, and beyond that beside CRP, the liver values and creatinine. Have blood drawn normally hydrated, seated, and compare over time at the same lab.