Blood and Plasma Specific Gravities and Plasma Formol Reactions in General Medical Conditions

Struthers, David (1949) Blood and Plasma Specific Gravities and Plasma Formol Reactions in General Medical Conditions. PhD thesis, University of Glasgow.

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No alterations have been suggested in the original technique. The theoretical considerations underlying the original formulae and nomograms depend upon basic formulae credited to Ashworth and Tigertt (1940) - Equations i - iii, facing this page. Equation i expresses the weight of 100 ml blood as the sum of the weights of the cells and the plasma. Phillips et al examined blood from twenty normal American males, estimating Gb and Gp by the copper sulphate method. H was measured after spinning for 60 minutes at 3000 r.p.m. in a centrifuge, radius 18 cm., and the Hb was estimated by a method which measures the oxygen + carbon monoxide capacity of the blood (see page38). The mean values so obtained were Gb=1.0595, Gp=1.0264, H=47% and Hb=15.9g./100 ml. Hence the mean M. C. Hb. Conc. = 33.9g./100 ml. packed red cells; the mean normal Gc calculated from these results by means of equation iii was 1,097. This mean normal Gc agreed with that found by Ashworth and Adams (1940) using the falling drop method of Barbour and Hamilton (1926). Equation iv is developed by substituting 1.097 for Gc in equation ii. Accepting 33.9 as the M. C. Hb. Conc. and H as in equation iv, equation v is obtained. Where Gp could not be estimated, as under war conditions, it is suggested that Gp should be assumed to be 1.0264. Substituting this figure for Gp in equation v, equation vi develops on simplification. Equation vii opposite, is based on the mean Gp of the twenty normal bloods examined and on current standards of normal g. protein/100 ml. plasma by micro and macro-Kjeldahl methods. Equations iv, v, and vii are incorporated in their nomogram (phillips et al 1945b). The originators state that the estimated specific gravities are accurate to within +0.00005, and point out that an error ten times greater has very little effect on the accuracy of the calculated H and Hb. In normal bloods they found that H and Hb, calculated from Gb and Op by means of equations iv and v,were accurate to within +2.0% and +0.3g. Hb% respectively; in abnormal bloods the corresponding error ranges were 9% for H and 0.7g. for Hb. Unfortunately they do not record the number of abnormal bloods examined or the nature of the abnormalities in the series. They do refer later to a series of abnormal bloods investigated by Atchley et al (1945) in which the Hb, calculated by equation vi from Gb alone, was accurate to within +1.5g. in 48 out of the 50 bloods examined. In this series there was one case in which this modified method gave an error of 4.7g. Hb%; the plasma proteins amounted to 12.7g.% plasma in this case. The authors conclude that Hb calculated from Gb alone is accurate to within +0.5g. "in bloods of the normal protein range." For the plasma proteins calculated from Gp by means of equation vi the error range in normal bloods was less than +0.3g./100 ml. plasma; in abnormal bloods the greatest errors seen were 0.6g. in nephritic cases. "Larger errors" they state, "are unlikely even in abnormal bloods.".

Item Type: Thesis (PhD)
Qualification Level: Doctoral
Keywords: Medicine, Histology
Date of Award: 1949
Depositing User: Enlighten Team
Unique ID: glathesis:1949-79709
Copyright: Copyright of this thesis is held by the author.
Date Deposited: 04 Mar 2020 15:21
Last Modified: 04 Mar 2020 15:21

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