Interstitial fluid is the body fluid between capillaries and cells, containing nutrients from capillaries by diffusion and holding waste products discharged by cells due to metabolism. 

Water, ions, and small solutes are continuously exchanged between them across the walls of capillaries, through pores and capillary clefts.

Interstitial fluid consists of a water solvent containing sugars, salts, fatty acids, amino acids, coenzymes, hormones, neurotransmitters, white blood cells and cell waste-products.

The plasma that filters through the blood capillaries into the interstitial fluid does not contain red blood cells or platelets as they are too large to pass through but can contain some white blood cells to help the immune system. 

Lymph fluid belongs to the extracellular fluid (ECF) compartment, specifically as part of the interstitial fluid.


Lymph is derived from interstitial fluid that enters lymphatic vessel