IT had been a standing assumption in medical literature that the albumin/globulin ratio (AGR) can potentially predict digestive system cancer outcomes. However, even as late as 2017, such an assumption had not been supported by scientifically convincing conclusions.
Albumin and globulin are two most important globular protein forms in the human blood circulation which function as transport proteins. Albumin, however, primarily functions as blood pressure regulator, while globulin functions in immune defenses. Albumin accounts for at least 50 percent of the total serum proteins. Local reference values usually set the total protein range at six to eight milligrams per deciliter (mg/dl). Meanwhile, albumin has a reference range of 3.5 to 5 mg/dl and globulin 2.3 to 3.5 mg/dl.
However, if you will add these values, the total will have a reference range of 5.8 to 8.5 mg/dl. Thus, technically, the total protein measured comprises the total values of albumin and globulin with only a minor variation of 0.2 mg/dl in the lower limit and 0.5 mg/dl in the upper limit. This discrepancy can be attributed to statistical variations associated with operational performance of the medical technologists performing the test, the machine functioning, and the standard samples used.
Analyzing these reference values this way can help you avoid unnecessary worries when your total protein results indicate a high value (e.g. 8.15 mg/dl) when, instead, it is within the 5.8 to 8.5 total protein range computed by adding the albumin and globulin ranges. Thus, even if the machine sets the total protein to read “high” at 8.1 mg/dl (remember the 6 to 8 mg/dl reference range), its effective high cutoff is really 8.6 mg/dl. This is particularly reasonable when your albumin and globulin levels are machine-read as “normal.”
Meanwhile, the normal AGR is often set at 0.8 to 2.0 (no unit, being a ratio).
Guo, Yuan, Chen and Zheng recently attempted to review the AGR literature so far to determine if a convincing conclusion may already be made in relation to the test’s prognostic potential. Using 13 studies and representing 9,269 patients, the team reported that low pretreatment (or baseline) AGR level (less than 0.8) had resulted in poor overall patient survival in digestive system cancers and worse disease-free survival and cancer-specific survival.
These questions may be too early to ask today. I suspect that a decade later may be a better time to ask these questions. However, it is for our students’ advantage that they learn the growing sophistication of international research protocols.
Asking the necessary questions, however, is as necessary. Voltaire said: “Judge a man by his questions rather than by his answers.” There are the questions. We will wait for the answers.