A Comparison between Glass and Lucite Cuvettes in Spectrophotometric Determination of Hemoglobin Oxygen Saturation

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 S_E = 2.0.

A significant although small difference therefore existed between y and x, increasing slightly with decreasing So₂

Key Words:

• Hemoglobin oxygen saturation
• Lucite cuvette
• spectrophotometry