The Plasma Viscosity in Pulmonary Tuberculosis

In 1940 T'ang and Wang (1) measured the erythrocyte sedimentation rate and the plasma viscosity in 176 cases of pulmonary tuberculosis and 56 cases of tuberculosis of other organs. These writers concluded from their data that the plasma viscosity determination may be a more sensitive test for activity of tuberculosis than the sedimentation rate. Independently, in 1942, Whittington (2) in a study of the mechanics of the erythrocyte sedimentation rate suggested that this procedure might with advantage be replaced by plasma viscosity measurements. The method was tried on 63 tuberculous patients by Miller and Whittington (3) who found that the plasma viscosity was a more reliable index of the clinical condition than the erythrocyte sedimentation rate. The general findings of the latter paper were confirmed by Houston, Harkness and Whittington (4) and by Harkness, Houston and Whittington (5) after 645 estimations of the plasma viscosity-223 of these were of pulmonary tuberculosis; 385 were of a variety of diseases and 37 were of normal persons. Although these data indicate that the plasma viscosity is significant in following the course of persons with pulmonary tuberculosis, they show emphatically that the test is non-specific. For the past 20 years the accepted laboratory method of estimating the general reaction of rheumatic diseases has been theerythrocyte sedimentation rate. From this earlier experience, a trial of the plasma viscosity test in rheumatic diseases also seemed desirable. Cowan and Harkness (6) have reported 320 viscosity estimations made at the Royal Infirmary, Sunderland, in various rheumatic diseases. They found that the viscosity test was much more reliable than the erythrocyte sedimentation rate, and that the measurements of viscosity appeared to be a promising method of investigation in rheumatic diseases. Woodmansey and Wilson (7) have reported similar findings. While Race (8) believes that in the more severe clinical conditions the plasma viscosity test is superior to the erythrocyte sedimentation rate, he considers that the erythrocyte sedimentation rate may be the more sensitive in detecting the earliest changes in rheumatic disease. The statistics of the present paper are based on the results obtained up to the end of February 1948, at Sunderland, and to the end of December 1947, at the Crossley Sanatorium (Table I). So far as we know, the subject of plasma viscosity has not yet been discussed in the American literature: our results are, therefore, presented in order that readers in the United States can form an opinion on what we consider to be the most useful of the physical, non-specific laboratory estimations.