Abstract
Karendal, Birgitta, Michaelsson, M. & Ström, G. A comparison between glass and Lucite cuvettes in spectrophotometric determination of hemoglobin oxygen saturation. Scand. J. clin. Lab. Invest. 22, 57-61, 1968. Hemoglobin oxygen saturation (So2) in human arterial or venous blood was determined by a spectrophotometric method, using a Lucite or a glass cuvette, and by a reflectometric method. With the Lucite cuvette a higher random error in duplicate analyses on the same sample (0.30-0.70 per cent saturation at So2 values between 30 and 98 per cent) was obtained than with the glass cuvette (0.25-0.38 per cent). With the reflectometric method the error in analyses on duplicate samples was 1.14 per cent, at values for So2 around a mean of 75 (range 26-98) per cent.
With the Lucite cuvette, the value of So2 was significantly higher (1.0-2.0 per cent saturation) than with the glass cuvette. The arterial So2 in young cardiac patients, whose So2 was expected to be normal, averaged 98.2 (S.D. 1.4) per cent with the Lucite cuvette in 134 cases (range 92.4-100.6), and 97.2 (S.D. 1.3) per cent with the glass cuvette in 151 cases (range 93.6-99.7).
Values of So2 by the spectrophotometric method (y, per cent), with the glass cuvette, were correlated to values of So2 by the reflectometric method (x, per cent) as y = 7.39+0.940 x, where b = 0.940±0.022, r = 0.986±0.038, and SE = 2.0.
A significant although small difference therefore existed between y and x, increasing slightly with decreasing So2