Blood tests make heart patients anemic

Many heart patients become anemic during hospitalization because of losing much blood after undergoing several laboratory tests, a new study warns. Researchers who reviewed the medical records of almost 18,000 patients with the history of heart attack found that one in every five or 20 percent of the studied patients develop moderate to severe anemia during their hospitalization period. Based on their findings, the researchers suggested that high amount of blood drawn for routine diagnostic tests is the main reason contributing to anemia in these patients. The average volume of blood drawn from patients who developed anemia was 173.8 milliliters (ml) which was more than double the 83.5 ml extracted from patients who didn't become anemic, scientists wrote in the Archives of Internal Medicine. The risk of moderate to severe hospital-acquired anemia increased by 18 percent for every 50 milliliters of blood drawn from a patient, the new study added. The resultant anemia persists for a month or more after discharge and may severely influence patient's recovery and health and even increase the risk of death, the researchers warned. "This is not just a lab abnormality," said lead author Mikhail Kosiborod from the University of Missouri. "These patients actually feel worse after they leave the hospital. Mortality is higher, too." Previous studies have also showed that about half of heart attack patients who had normal red blood cell count or hemoglobin level at the time of hospital admission became anemic at the time of discharge. The majority of those patients had no bleeding complications that could account for the condition. The findings of the present study are not enough to conclude that unnecessary tests are being done. In addition, less testing could also result in medical problems, researchers noted. "A lot of the blood work done in a hospital is very important and necessary," Kosiborod said. "But the volume of blood drawn is a risk factor. This hasn't been on the radar screen. We don't think about there being a downside (to blood tests)." The study authors urged physicians to follow the guidelines and apply standard measurements to reduce the number of unnecessary blood samplings and also the extra blood drawn for each exam. "Pediatric tubes are perfectly adequate for most of the tests that need to be done and can drastically reduce the amount of blood lost," Kosiborod said.