Capillary blood tests (fingertip prick) can be used as an alternative test to intravenous tests, according to a study by the Clínica Universidad de Navarra published in the journal Diagnosticsfrom the international academic press De Gruyter.
The study, led by Dr. Álvaro González, director of the Clinic’s Biochemistry Service, reveals that taking capillary samples would promote telemedicinewould facilitate the management of chronic patients by reducing their visits to a hospital center and, in addition, it is perceived as a less invasive and painful method.
A painless process that can be performed by the patient
“Obtaining capillary blood is a process relatively painlesswhich can be carried out by the patient himself and in which small volumes of blood can be obtained”, recalls González, who adds that this advance responds to “a growing need” to obtain samples without having to go to a health center.
“Its implantation can be very useful for people with limited access to extraction centers, with needle phobias or hospitals, and for children, the elderly or the chronically ill who require minimal samples”, acknowledges the expert.
The investigation has had 296 patients who have taken a sample of both venous (349 samples) and capillary (427 samples) blood to make a comparison of 40 biochemical parameters and who have shown that the capillary samples reflected a mean index of hemolysis, which shows the deterioration of the red blood cells, somewhat higher, but with an acceptable and valid sample quality In most cases. While the rest of the indices, both lipemic (blood lipid concentration) and icteric (blood bilirubin level), have reflected similar values.
Challenges for implementation
Another of the objectives of this study was to determine the patient satisfaction before this new analytical approach. Almost two thirds (64.70%) of those consulted who must undergo at least one annual analysis have highlighted this benefit.
“Although this type of analysis facilitates its realization at home by the patient himself with the appropriate safety and quality controls, it is important to take into account the time elapsed between taking the sample and its receipt in the laboratory, since the results may vary after 24 hours, and that its transport is safe, both for traceability as well as for the stability of the sample”, emphasizes González.
The possible implementation of this methodology implies other challenges for clinical laboratories, such as the installation of the necessary equipment capable of analyzing such small volumes of samples.
Make it a routine process
“Capillary blood has certain characteristics and a composition different from that of venous blood, since it is a mixture of blood from arterioles, from the capillaries themselves and the venules. Therefore, the concentrations of analytes may be different from those found in venous blood and it must be ensured that the reference values used are correct and that the clinical interpretation is adequate,” he stated.
This research for the validation of capillary blood analysis is a first step to be able to make it a routine process that maintains the quality in the extractions, a stability in the sample and is capable of analyzing more and more magnitudes, as is done in the analysis of venous blood.
References
Maroto-Garcia J, Deza S, Fuentes-Bullejos P, Fernandez-Tomas P, Martinez-Espartosa D, Marcos-Jubilar M, Varo N, Gonzalez Á. Analysis of common biomarkers in capillary blood in routine clinical laboratory. Preanalytical and analytical comparison with venous blood. Diagnosis (Berl) (2023) DOI: 10.1515/dx-2022-0126.