The Rwanda health service consists of a referral system encompassing three levels of health care: referral, district and health center levels. In the whole country, there are four referral hospitals, 34 district hospitals, and 385 health centers. At the central level, the NRL's mandate is to provide referral laboratory services to all health-care providers in the country, to prepare and distribute laboratory specimen transport media, to develop policies and to enforce standards for all laboratories in the country. The NRL also oversees the licensing, certification and accreditation of private and public health laboratories.