CBS.com; CBS All Access; CBS News; CBSN; Watching Live TV. All Access Live TV; TV Provider
Thick blood may also be caused by the presence of harmful pathogens such as fungi, viruses, bacteria, and parasites. These pathogens can actually activate a coagulation response in the body as a way to avoid being attacked by the bodyâs immune system.
Too many red blood cells is referred to by doctors as polycythaemia and erythrocytosis.The main problem caused by polycythaemia is that the high number of red cells increases the blood's 'thickness' (viscosity).