The term body fluid refers to the water and also the SOLUTES of your body.
The body fluid is made up majorly of water and different types of solutes. The solutes are classified as large and small. The small solutes are made up of electrolytes and metabolites. The large solutes are made up of proteins, enzymes and serum albumin.<span />
If you don't know how that kind of thing works, you are likely to make mistakes regarding it. If you know how it works, you can prevent yourself from making mistakes that could endanger yourself and/or others.