07/14/2026
Our blood can tell us a lot about how our bodies are functioning and what they are doing to maintain homeostasis.
Blood is made up of four main components: plasma, red blood cells, white blood cells, and platelets. Plasma is the liquid portion and is mostly water, while red blood cells carry oxygen, white blood cells help fight infection, and platelets help our blood clot.
One common measurement we can look at is hematocrit, which tells us what percentage of our blood volume is made up of red blood cells. Normal ranges vary, but are generally around 36–46% for women and 41–53% for men.
A hematocrit that is too high or too low can give us clues about what may be happening in the body. Hydration status, blood loss, anemia, kidney function, chronic low oxygen levels, smoking, altitude, and certain medical conditions can all influence hematocrit.
Even something as simple as dehydration can change the number. When we lose water, plasma volume decreases and our blood becomes more concentrated, causing hematocrit to appear higher—even though we haven’t necessarily made more red blood cells.
No single lab value tells the whole story, but bloodwork gives us valuable information about how the body is responding, adapting, and working to maintain balance.
