Msu and Mcs are abbreviations for two seperate medical terms. They are not related. These will be indicated on the results of a blood test.
Msu - Monosodium Urate (Blood Test)
This is a blood test which tests for high levels of uric acid. Uric acid is a chemical produced by the human body to break down some kinds of food such as herring. Usually it is filtered out of the body by the kidneys.
High levels of uric acid can be a contributor to conditions like gout. It can also lead to kidney stones.
Mcs - Multiple Chemical Sensitivity
Multiple Chemical Sensitivity is a condition in which the individual experiences a negative physical reaction when they are exposed to even tiny amounts of commonplace chemicals (such as perfume or pesticides). One or more symptoms can be elevated due to these chemicals.
Checking for Mcs in a blood test
In relation to a blood test, this is usually conducted to detect allergies or other anomalies in the blood before this condition is diagnosed.
Very little is known about this condition and research is ongoing. Although some doctors attribute it to issues with an immune deficiency.