Difference Between Blood and Lymph

• Blood: Blood is thick, opaque, and bright red. The red color comes entirely from the millions of Red Blood Cells (RBCs) carrying a protein called hemoglobin. Blood also contains White Blood Cells, platelets, and plasma.
• Lymph: Lymph is completely colorless (or slightly pale yellow) and watery. This is because lymph contains absolutely zero Red Blood Cells. It is made almost entirely of blood plasma and White Blood Cells (specifically lymphocytes).

• Blood: It acts as a massive delivery system. Blood delivers vital oxygen and nutrients to every single organ and cell in the body, while carrying away toxic carbon dioxide waste.
• Lymph: It acts as a defense and drainage system. Its primary job is to transport White Blood Cells to fight off massive bacterial infections, and to drain excess leaked fluid from the tissues back into the bloodstream.

• Blood: The flow is bidirectional (two-way). The heart pumps oxygenated blood outward through arteries, and deoxygenated blood returns back to the heart through veins.
• Lymph: The flow is strictly unidirectional (one-way). Lymph can only flow upwards from the body tissues towards the heart, where it eventually dumps into the veins.

Blood is forcefully pumped around the body by a massive, muscular engine: the Heart. Lymph has no central pump. It moves very slowly, squeezed upwards entirely by the physical movement of your skeletal muscles when you walk or exercise.