Speaking during the World Blood Donor Day on Saturday, Mbere said HIV infections have reduced the pool of blood donors while simultaneously increasing blood utilisation demands.
She said statistics for the first quarter of 2008 indicate that HIV-related transfusions alone are equivalent to all the units used for accidents and maternity cases.
"The result is that some patients have had to go without much needed transfusion in the face of acute blood shortages," Mbere said.
She added that only two percent of the blood-donated came from regular blood donors.
She said that this is as a result of fears and misconceptions that may deter people from donating blood.
However, she asserted that healthy people should be encouraged to donate blood because this has personal and social benefits and minimal risks.
Mbere noted that donating blood ensures regular health checks, encourages maintenance of healthy lifestyles and earns recognition from the community.
She said for the National Blood Service, donating blood is a life-saving measure in emergencies and life-threatening situations. Mbere said HIV, hepatitis viruses and other transfusion transmissible infections are lower among voluntary, unpaid donors.
She said 60 percent of the blood collected comes from secondary school students. Blood donation drives and volunteers who visit centres in Gaborone and Francistown account for 40 percent.
Mbere said through improved donor screening and testing, the rate of discarded blood has been reduced by 10 percent in the last four years. The discard rate due to HIV alone has been reduced by five percent to 2.1 percent.
"This increase in the level of blood safety reflects the efforts made by multiple players in promoting risk reduction and screening capacity," Mbere said. She added that Botswana has managed to meet World Health Organisation (WHO) targets of ensuring blood safety by the year 2012.
According to the strategy, 75 percent of all African countries will have adopted and implemented national blood transfusion policies and have at least 80 percent of blood collected from voluntary non-remunerated blood donors. The strategy calls for donated blood to be tested for HIV and at least 80 percent of other transfusion transmissible infections.
Mbere said Botswana is one of the few countries that have managed to reach these targets before the 2012 deadline. "We could not have achieved these results without the commitment of thousands of donors whose blood is donated for purely altruistic reasons."
She however said Botswana is still faced with a challenge of how to expand the pool of regular donors to fulfill the volume requirements.