Proteins account for a large amount of the dissolved substances in plasma/serum. These proteins are a very heterogenous group of over a thousand individual proteins, with a variety of functions including maintenance of oncotic pressure, transportation of substances, coagulation, etc.
In this section, we will cover the following:
- Laboratory indicators of protein disorders: total protein and albumin are measured parameters; globulins and albumin:globulin ratio (A:G) are calculated from these.
- Total protein
- Albumin
- Globulins
- Albumin to Globulin ratio (A:G)
- Ammonia and uric acid – both are by-products of protein metabolism
- Electrophoretic patterns
- Acute phase proteins
- Immunoglobulins
- Failure of passive transfer
The test results on a chemistry panel provide quantitative values for the major proteins. However, there are many proteins found within the globulin fraction and the total globulin result does not provide information on these fractions. Electrophoresis, in contrast, provides both quantitative and qualitative data for the different fractions that comprise total protein and can be used on serum, urine or body cavity fluid samples (e.g. cerebrospinal fluid). Ammonia and uric acid are by-products of protein metabolism. More information on ammonia is found under liver tests.
