The blood is of no use since it cannot be screened for HIV, Syphilis and Hepatitis B and C.
The warning on the dwindling stock of reagents was first raised in 2019, but adequate reagents to screen blood is yet to be procured.
Data accessed by KTN News showed that KNH is the biggest consumer of blood from the unit at 1,711 units of blood and blood components consumed between January 1, 2019 and December 31, 2019.
It is followed by Mama Lucy Hospital (1,436), Pumwani Maternity (1,378), Nairobi Outpatient Centre (1,344) and Mbagathi Hospital (1,325).
Health CS Mutahi Kagwe has attributed the shortage to the illegal sale of blood within and outside the country, "making the situation worse than it would otherwise be".
The ministry appealed to the Director of Criminal Investigation, George Kinoti, to step in and address the matter of cartels in the blood business.
However, a significant contributor to the situation is closed funding.
The vast majority of funding for blood collection - some 80 per cent - came from outside donors, according to a recent government report.
This ensured there was money for essential supplies, personnel and other blood safety-related costs. The main donor was the US government, through the President’s Emergency Plan for Aids Relief - known as Pepfar. It’s a programme to help save the lives of those suffering from HIV/Aids around the world.
Kenya was a major beneficiary of this, but funding was cut back last September, as a result of which supplies and equipment for the blood supply programme stopped.
The CS said the ministry is also looking into technological ways to trace blood.
Kagwe said, "The transition between Pepfar funding and national government funding ...did not occur as it was supposed to."
He added that there have been supporters, like the World Bank, who are willing to step in and bridge the gap before Kenya takes up self-funding.
The Ministry of Health has started a campaign for the public to donate blood to mitigate the current shortage in the country.
The first event was marked on Saturday at Landi Mawe in Eastlands, Nairobi.