Haemoglobin estimation

Haemoglobin estimations are necessary at least every 6 months to check adequacy of therapy and for early detection of iron deficiency anaemia due to achlorhydria (common in patients with pernicious anaemia > 60 years) or carcinoma of the stomach, which occurs in about 5% of patients with pernicious anaemia. 

Goldstein DE, Little RR, Wiedmeyer H-M, England JD, Rohlfing CG. Glycated haemoglobin estimation in the 1990s A review of assay methods and clinical, interpretation. In Marshall SM, Home PD, eds. The Diabetes Annual. New York Elsevier Science B. V., 1994 193-212. 

The toxic effects of cyanide and sulphide are chiefly due to combination of these substances with the Fe " " of cytochrome oxidase so that the final reaction of the respiratory chain is blocked. Cyanide and sulphide, however, also have the effect of converting haemoglobin into cyan-methaemoglobin and sulph-methaemoglobin respectively. Both are stable compounds and once formed can only be removed by complete degradation. Cyan-methaemoglobin is used as a stable and reproducible standard in haemoglobin estimations. 

In Britain, the estimation of blood lead is now common practice. Blood lead (PbB) estimations were performed on exposed workers by the Employment Medical Advisory Service from around 1974, in conjunction with the legally required haemoglobin estimation. PbB estimation at regular intervals for certain categories of lead worker became mandatory in 1980 (Control of Lead at Work Regulations, 1980). 

Betke, K. Marti, H. R. and Schllcht, I. "Estimation of Small Percentages of Foetal Haemoglobin". Nature,... 

In the model of Csanady et al. (1996), the biochemical parameters for butadiene in rats and mice were obtained by fitting model simulations to in-vivo data of Bolt et al. (1984) and Kreiling et al. (1986). The biochemical parameters for epoxybutene were identical to those of Johanson and Filser (1993, 1996). This model accurately predicted experimental data on epoxybutene. The most advanced models are those of Csanady etal. (1996) and Sweeney et al. (1997), since they can simulate both epoxybutene and diepoxybutane as metabolites of butadiene. The tissue blood partition coefficients for diepoxybutane were estimated by Csanady et al. (1996) to have a value of 1 for all tissues. Sweeney et al. (1997) obtained tissue blood partition coefficients from in-vitro measurements (Table 23). Both models yielded good predictions for mice and rats for both metabolites. For humans, no measured data have been reported against which the predictions could be validated. In addition, the model of Csanady et al. (1996) predicted accurately the measured haemoglobin adduct levels (Osterman-Golkar etal., 1993 Albrecht et al., 1993) of epoxybutene in rodents following exposure to butadiene. None of the models published has included the fonnation and elimination of epoxybutanediol. 

Non-thresholded chemicals that are not carcinogens are less frequently identified. For many years lead was considered to be thresholded because its effects on haemoglobin synthesis were not seen at low doses. However, recent work into the effects of lead on mental development suggest that there may be no threshold for this end-point. Food is a relatively minor source of lead exposure compared with air and dust in urban environments. For chemicals that relate to toxicological end-points that do not show thresholds it is not possible to identify a NOAEL or PTWI. In such cases it is desirable to estimate the level of risk associated with a given level of exposure. 

Indicine JV-oxide (53) is an anti-cancer drug that is now undergoing clinical trials. Methods for its estimation include oxidation to the pyrrole derivative and treatment with Ehrlich s reagent,53 g.l.c. analysis of its trimethylsilyl derivatives,54 and differential pulse radiography.55 The aqueous degradation of indicine iV-oxide (53) to retronecine /V-oxide and (—)-trachelanthic acid has been studied.56 Indicine jV-oxide is reduced to indicine by Fem, by reduced cytochrome c, by ascorbic acid, and by denatured haemoglobin.57... 

Subjecting this data to a two-sample t-test, we find that the point estimate for the difference between mean haemoglobin levels (expressed as suspect drug — control) is —2.51 g/1 witha95 per cent confidence interval of—0.294 to —4.728 g/1. As zero is excluded from the interval, there is significant evidence of a difference in haemoglobin levels. 

It is estimated that 100 000 homozygotes are born each year in Africa, 1500 in the USA, 700 in the Caribbean, and 140 in the UK. Haemoglobin S is also common in Cyprus, Greece, Italy, the Middle East and in populations who originate from these areas. 

Q10 The transfer of CO across the respiratory surface (TCo) can be used to estimate the efficiency of gas transfer in the lung. A small concentration of CO is added to inspired air it diffuses across the alveolar membranes into the blood. The increase in arterial blood content of CO over a short period of time is measured to estimate the rate of CO transfer. A small concentration of CO must be used as this gas combines strongly with haemoglobin at the same position as oxygen to produce carboxyhaemoglobin. 

The effect caused by haemolysis has been estimated by referring to haemoglobin concentration. 

K21. Kynoch, P. A. M., and Lehmann, H., Rapid estimation (2J hours) of glycosylated haemoglobin for routine purposes. Lancet 2, 16 (1977). 

Menez, J. F., Meskar, A., Lucas, D., Darragon, T., Floch, H. H., and Bardou, L. G., Glycosylated haemoglobin and serum proteins Semi-automated estimations. Clin. Chem. 27, 1947-1948 (1981). 

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