Albumin/globulin ratio

Your blood protein consists of two halves that come from different corners. Albumin, more than half, is made by your liver; it keeps fluid in the vessels and carries hormones and fatty acids. Globulin is the rest: transport proteins, clotting proteins, inflammatory proteins and above all the antibodies, which your immune system makes. In a healthy person there is more albumin than globulin, and the albumin/globulin ratio, albumin divided by globulin, therefore comes out above one. The ratio does one thing that albumin and globulin cannot do separately: it is independent of how concentrated your blood was that day. If you arrive dehydrated at the draw, albumin and globulin both rise, and total protein with them; if you have drunk a lot, they both fall. The ratio between the two stays virtually the same in both cases. If the ratio does move, something has really shifted between what your liver makes and what your immune system makes. Your report usually does not print the ratio; you calculate it with the calculator on this page, from albumin and total protein in g/L from the same draw. The result has no unit. Because it is a calculation, nobody publishes a band for it; calculated from the middle of their bands a healthy adult comes out around 1.15 to 1.64. Below one the ratio is reversed, and that is always a reason to look further.

Albumin and globulin move against each other in most diseases. In an inflammation or infection that lasts for months your liver makes less albumin, because it shifts its protein production to inflammatory proteins, while your immune system makes more antibodies; the ratio then falls on two sides at once. In a liver with scars the same happens: less albumin, and more antibodies because the liver clears them less. The ratio catches that scissors in one number, and does so regardless of how much you drank. The second reason is that the ratio can unmask a normal total protein. A falling albumin that is filled up by a rising globulin leaves the total untouched; the ratio does show the shift. Anyone who has their blood tested yearly often sees a smouldering inflammation or a liver going downhill earlier in a falling ratio than in the separate numbers. The honest limitation is that the ratio is a pointer and not a verdict. It says that the distribution shifted, not why, and the cause lies in the two values it follows from. There is no published band, so your own course is the reference point, and a shift should always be read beside albumin, globulin, CRP and the liver values.

A low ratio means there is proportionally less albumin or more globulin, and that is the side to take seriously. Usually it is the first and rarely the last: a liver making less albumin, through scars, alcohol or fatty change; protein loss through the kidneys, where albumin leaks away and the urine foams; a long-standing inflammation or infection, where albumin falls and the antibodies rise; and rarely an abnormal protein from a single cell line in the bone marrow, which lifts globulin without there being an inflammation. A high ratio means proportionally little globulin, and that is usually harmless: a globulin that sits on the low side with no clear cause, in someone who is healthy and drinks normally. Rarely the immune system makes too few antibodies, inborn or through medicines that suppress it, and then recurring infections are the hallmark. A high albumin on its own does not lift the ratio, because that comes from dehydration and then globulin rises with it. The ratio belongs beside albumin and globulin themselves, because the ratio says which side shifted and the two numbers say why, beside total protein and your fluid balance, and beside CRP, ALT and gamma-GT, which show whether an inflammation or your liver sits behind it.