It may surprise most readers to learn that the primary cause of anemia among preterm infants during the first weeks of life is blood loss due to laboratory testing. That is why researchers from the University of Iowa decided to check and see if blood was being taken in excess of what was actually required by the laboratories. To summarize:

• Blood samples drawn from premature newborns were weighed, and selected clinical data were recorded, including:

  • test performed
  • blood collection container used
  • infant's location (ie, intensive care unit [NICU] or intermediate intensive care unit)
  • infant's weight at sampling
  • phlebotomist's level of experience

  • work shift

• Blood collection containers were classified as tubes with marked fill-lines on the outside wall, tubes without fill-lines, and syringes.

• Infants were classified by weight into 3 groups: <1 kg, 1 to 2 kg, and >2 kg.

• The volume of blood withdrawn was expressed as a percentage of the volume requested by the hospital laboratory.

• The average volume of blood drawn for the 578 tests drawn exceeded that requested by the hospital laboratory by nearly 20%.

• The risk factors identified for greater blood overdraw included:

  • Collection in blood containers without fill-lines or syringes
  • Lighter weight infants
  • Critically ill infants being cared for in the NICU

  • Blood drawn during the evening shift

• There was also a significant variation in blood overdraw among individual phlebotomists.

Researchers conclude that "Significant volumes of blood loss are attributable to overdraw for laboratory testing. This occurrence likely exacerbates the anemia of prematurity and may increase the need for transfusions in some infants. Attempts should be made to correct the factors involved."

They suggest some common-sense measures to minimize this problem:

• Only tubes with fill-lines marked on the outside should be used.

• Educating individual phlebotomists, nurses, and other staff on reducing unnecessary blood loss (eg, ordering only essential blood tests, exercising the greatest care in the smallest infants, practice in drawing blood samples into syringes, etc.)

• Developing tests which require smaller blood samples

• More reproducible and better capillary blood sampling containers

• The use of point-of-care laboratory testing in which little to no blood loss results

Pediatrics August 2000; 106: e19

Dr. Mercola's Comments:

It may be possible for parents to help prevent the excess blood loss in their preterm babies, should they find themselves in this unfortunate position. First of all, they need to stay on top of the doctors and staff and ask questions about each and every test ordered. With good communication with the doctors and other staff, it may be possible that some of the tests may be avoidable. For example, if the hospital "policy" says blood should be taken every 8 hours, but the pediatrician feels that the previous results are good or improving and don't warrant testing that often, he (or she) might put in special orders for testing only at wider intervalsor not at all. Yet without the parents intervention, the doctor may be too busy to think of it. He may also be unaware of studies such as this one showing how much blood is lost in this manner. Many doctors simply don't keep up with current studies bacause they don't have the time. That is one of the biggest values in this newsletter. There are other things as well that can be done to prevent the excess blood loss described in the study. The study noted that overdrawing blood was much more prevalent when "marked" blood collection tubes were used. In other words, a few simple lines on the outside of the tubes could make a big difference. The authors noted with some astonishment that unmarked tubes were even being used. Parents should INSIST on marked tubes. This will also help to change the system as hospitals will note the parental advocacy and possibly only order marked tubes in the future. The authors also noted more excess blood when syringes were used rather than tubes. Again, parents can use this knowledge to insist on only MARKED tubes (no unmarked tubes and no syringes). Lastly, clamping the umbilical cord as late as possible during the birth allows a tremendous amount of additional blood to get to the baby (known as 'placental transfusion'). The volume of transfused blood varies between 20% and 50% of the total newborn's blood volume, depending on when the cord is clamped and at what level the baby is held prior to clamping (European Journal of Pediatrics 1981; 137:141-146. Clinical Perinatology 1982; 9: 559-593). Delayed cord clamping is especially important with preemies. The more blood and iron the babies have, the less likely or severe any anemia will be later and the more blood they will have to be used for testing. This has been confirmed by several studies (abstract 1 , abstract 2). Parents can help to insure that the cord is clamped too early by discussing the matter with their OB/GYNs early in the pregnancy.