Before the modern vacuum tube, blood collecting systems and devices were difficult and imprecise. Etched lines in borosilicate glass tubes reflected the amount of blood the phlebotomist needed to collect.
Using a needle, the phlebotomist would puncture a vein (typically in a person's arm) and direct the blood into the glass tube.
The tubes contained ETDA or citrate as additives to prevent blood coagulation. Black rubber stoppers were used to seal the tubes for transportation to the laboratory.
Sanitation was also an issue because tubes and syringes were washed between patients. A grinding wheel was used to resharpen needles, and they were sterilized between uses.
A Timeline Showing the Evolution of Blood Collection
Joseph Kleiner invented a modern glass vacuum tube called the Evacutainer. Becton, Dickinson and Company later changed and trademarked the name Vacutainer.
1991 - 1993
The Becton Dickinson Research Center developed a plastic version, called Vacutainer PLUS. In a vacuum tube, the vacuum pressure ensures that the correct volume of blood enters the tube from the needle. One end of the needle punctures the vein, while the other end goes through the rubber stopper into the tube itself.
Standardization of blood collection tubes
This standardization ensured that additives were used in the correct proportion for the amount of blood collected. The vacuum tubes used in venipuncture made blood draws safer and easier, and their results more accurate. Regulatory agencies such as the FDA, ISO, and CLSI now enforce guidelines that ensure that blood collection systems are consistent in both design and manufacture.
Dried blood spot (DBS) sampling
DBS was an advancement on collecting blood using vacuum tubes, ushering in a new approach for general use. With DBS sampling, a small prick of blood is dropped onto an absorbent card made of filter paper. After the DBS card absorbs the blood and dries sufficiently, it can be transported much more easily than glass tubes filled with blood samples.
The innovation of DBS cards means that a very tiny sample of blood can provide accurate test results, a boon for everyone, including researchers, hospitals, and technical staff.
However, one drawback of DBS sampling is that the filter paper absorbs the blood unevenly, causing variation in the blood sample.
Volumetric Absorptive Microsampling
Although the DBS approach to blood collection was innovative, its limitations in delivering precise sample volumes led researchers to develop even more advanced blood collection methods.
One such advance was volumetric absorptive microsampling, which was developed to overcome DBS limitations for the modern clinical lab. Launched in 2015, one of the first examples of volumetric absorptive microsampling was the Mitra® device based on a patented VAMS® technology. As reported in many published scientific journal articles, the Mitra device with VAMS consistently delivers fixed-volume blood samples and overcomes the limitations and hematrocrit bias that was reported with DBS cards.
To read peer-reviewed articles discussing studies and programs that have applied volumetric absorptive microsampling, visit our Technical Resource Library by following the link below: