This is the foundational test for any abnormal fluid buildup. Your doctor collects a sample of the fluid (e.g., from the lungs or abdomen), and our lab performs a comprehensive routine analysis. This includes a cell count and a microscopic examination to look for the cause, be it inflammation, infection, or other cellular abnormalities. This test is the essential first step, providing your doctor with the vital, broad-spectrum data needed to understand the cause of the fluid buildup.