Gri-Cel micro-hematocrit technology

Faster, more efficient measurement of red blood cell volume

Technical file

Type of innovation: System

Scope: Clinical Analysis

Innovation leader: Grifols i Lucas, Víctor

Year: 1960

Period: 1909-1971

Geographical scope: Spain

Economic impact: High

Level of innovation: Evolutionary

Patent: Yes

Interdisciplinary connections: Glass manufacturers

The early days of red blood cell measurement

Today, donated blood undergoes sophisticated screening and sterilization techniques both to monitor donor health and to ensure the quality of the blood itself. And blood testing is an important diagnostic technique to help ensure that patients receive the best care possible. Many of these techniques are relatively recent innovations (for example, testing blood for the HIV virus). Others have a longer pedigree: ABO blood group testing, for instance, was widespread by the 1930s, having been identified by Austrian biologist, Karl Landsteiner, in 1901.

One of the most basic pieces of information for blood banks and physicians alike was the proportion of oxygen-carrying red blood cells in an individual's bloodstream. This could be measured by using complicated procedures to determine the density of the blood, and this information could then be employed to calculate the proportion of red cells in it. However, such techniques were inefficient and by the 1940s the most common method was to place blood in a graduated tube, which was then centrifuged, causing the red cells to separate from the plasma. The volume of red cells could then be calibrated by a visual check against the scale on the side of the tube.

“Grifols was responsible for making this technology available in Spain, through the manufacture and distribution of centrifuges, capillary tubes, readers, and notebooks.”

Smaller, better, faster: the benefits of micro-hematocrit technology

Yet this process was cumbersome: standard laboratory centrifuges were slow, they could only process a few test tubes at a time, large blood samples were required, and the measurements were somewhat approximate. Following the end of World War Two, laboratory equipment was gradually displaced by technology that had been specially developed to measure red blood cell volume. This included micro-hematocrit centrifuges, which were three times faster than the standard laboratory equipment of the day. They employed a slightly conical plate that reduced vibrations to zero, with the result that the centrifuge did not require a protective lid, further speeding up processing time by eliminating a stage in the process. At the same time, normal test tubes were replaced by very thin capillary tubes, which meant that far smaller quantities of blood were required for analysis. Once centrifuging was complete, the tube was held up against a chart or micro-hematocrit reader and the results were recorded. This meant that, for the first time, it was possible to read the analysis results directly.

Grifols was responsible for making this technology available in Spain, through the manufacture and distribution of centrifuges, capillary tubes, readers, and notebooks. This initiative meant that the Spanish market was soon dominated by Gri-Cel centrifuges and this, in turn, helped ensure demand for accessories, in particular the capillary tubes, as the Gri-Cel microhematocrit used 70 mm tubes (as against the 75 mm tubes employed in many rival products).

Modern technology, ancient traditions

As the design of the centrifuges evolved and improved, so too did the design of the capillary tubes. The first tubes distributed by Gri-Cel were made of lead crystal. These were superseded by tubes manufactured from Murano glass, drawing on the skills and techniques of Venetian craftsmen. These, in turn, were replaced by tubes produced by Grifols' partner company, Dade. In all, Gri-Cel manufactured and distributed more than 11,000 hematocrit centrifuge units.


  • Grifols, S.A. (2011). ¿Y si lo hacemos así? Patentes de Víctor Grífols i Lucas. Barcelona: Grifols, S.A.
  • Gri-Cel, S.A. [ca. 1960]. Aparatos científicos. [Sales brochure]. Barcelona: Gri-Cel, S.A.
  • Phillips, R.A.; Van Slyke, D. V.; Kendall, E. Jr; Hamilton, P. B. y Archibald, R. M. (1945). Copper sulfate method for measuring specific properties of whole blood and plasma. New York: Josiah Macy Jr. Foundation.
  • Grifols, S.A. (2001). Dedicado a la vida... Barcelona: Probitas Pharma, S.A.