"In most hospitals the blood situation is tragic in August," Balina Bozova, head of the transfusion unit at a hospital in the southern town of Haskovo told the Standard newspaper.
"Now our ward has only minimum supplies of blood for every type and if we are faced with a major situation where large quantities of blood have to be given to patients, we will have trouble coping with it."
This has forced leading Bulgarian hospitals to postpone scheduled surgery as there is neither enough blood nor enough free beds in intensive care wards.
"We hardly manage to cover the emergencies let alone planned operations" with existing blood supplies, the head of the National Transfusion Haematology Centre, Andrey Andreev, told AFP.
"We are postponing scheduled operations because there is no room in intensive care because of crash victims," the director of the Military Medical Academy Stoyan Tonev also told journalists recently, adding that the situation on Bulgaria's roads was a "real disaster."
According to Andreev, an emergency patient needs three times as much blood as a regular patient during surgery.
"Sometimes we gave them less than the necessary, but they lived," he said.
Every year, an average 1,000 people are killed and 10,000 injured on Bulgaria's roads, a figure that a recent World Bank road safety study deemed too high for a country of 7.6 million people, and which exceeds the European Union average by around 20 percent.
Bad drivers and poorly-maintained roads are cited as the major cause.
The figures also increase in the summer as more people, especially motorcyclists, take to the road.
"During the summer months 80 percent of all our patients are crash injuries," Military Medical Academy intensive ward chief Nikolay Petrov told bTV television last week.
Doctors have called for people who cause car accidents to serve as hospital volunteers or be obliged to donate blood to ease the acute shortage of voluntary blood donors.
"There were 152,000 blood donations in 2007, which is a rate of 19.7 per 1,000 people compared to an European average of 22-26 per 1,000," Andreev said.
Besides, only 10 to 15 percent of donations are voluntary, he explained.
Patients' relatives, secretly pressured by hospitals to donate blood in order to guarantee a quick operation, provide as much as 80 percent of supplies.
Without these semi-illegal donations, many patients would have to wait a long time before a planned operation.
"My father had two operations: one was an emergency and they did not ask us to donate blood then, but the second was a planned one and doctors told me that a relative had to donate blood for it," a 60-year-old chemist who refused to be named, told AFP.
Some have turned this into a business.
A few gypsies queue at all times outside the blood donor centre in downtown Sofia ready to donate blood, but only for a price, which can go as high as 200-300 leva (100-150 euros) for a sack of 0.45 litres.
Four years ago, the same amount was worth 40 leva, according to the chemist, who bought blood for her father's operation.
"The blame for the blood trade is shared by those who sell and those who buy," said Andreev.
Blood trade is punishable by up to five years imprisonment but is practically impossible to prove, as buyers are reluctant to testify against illegal blood-selling gangs.
"Demand drives supply. If we could encourage more people to donate freely and fully cover hospital needs, those men would disappear at once," Andreev said.
Bulgaria has experienced blood donation problems ever since the fall of communism, before which all army soldiers were obliged to donate blood.
Rumours about possible infections and blood trade have also discouraged otherwise willing people from donating, Andreev added.