Red cell size and air composition

Factors influencing haematological measurements in healthy adults

By studying 516 healthy adults normal reference intervals were established for the Coulter "S" haematological indices with the plasma ferritin, B12, folate and red cell folate in a subgroup of 306. Significant sex related differences were found for all measurements other than MCV, MCH and B12. After allowing for these sex related differences, the effects of age, body size, fasting, smoking, alcohol, exercise and contraceptive pill usage on the parameters studied was defined.

The laboratory evaluation of microcytic red blood cells

Microcytic red blood cell states are common clinical problems in both adult and pediatric age groups. The recent widespread availability of electronic blood cell counters for performing routine blood counts has increased the detection of microcytic red blood cells. Physicians must workup both symptomatic and asymptomatic patients with microcytic red blood cells before they can initiate proper therapy and/or counseling. The purpose of this review is threefold: (1) to discuss the causes of microcytic red blood cells in terms of disorders of decreased heme production vs. disorders of decreased globin production, (2) to review the clinical laboratory tests useful in differentiating microcytic red blood cell states, and (3) to present a practical approach for the laboratory workup of microcytic red blood cells.

Blood cells and alcohol consumption with special reference to smoking habits

In the course of the Paris study on risk factors of cardiovascular disease in a large professional group, 7710 active and apparently healthy men aged between 48 and 54 were examined. This study measured the relationship between clinical abnormalities suggesting alcoholic liver disease (ALD) and the following blood parameters: white (WBC) and red (RBC) blood cell counts, haematocrit (H), and mean corpuscular volume (MCV), the former computed as H/RBC ratio. A subsequent analysis was performed on a random sample of 485 subjects without ALD who were questioned on their daily average alcohol consumption. Each subject was classified as ;smoker' or ;non-smoker' according to his daily tobacco consumption for the last five years. Analysis of the data confirmed that smoking and alcohol were related to the blood parameters; but, according to smoking habit, different relationships between alcohol consumption (or ALD) and MCV, RBC, or WBC counts were found: for smokers, RBC count significantly decreased and MCV increased with alcohol consumption (or ALD); for non-smokers, WBC count significantly increased with alcohol consumption (or ALD). So, it would be of interest to consider the relation between alcohol and tobacco in interpreting possible changes in blood parameters and in formulating hypotheses on the mechanisms of their specific action.

Haematological changes during normal pregnancy: iron induced macrocytosis

Haematological indices in 300 pregnant and 50 non-pregnant women were obtained by Coulter Counter analysis. In 47 women who did not receive iron supplements during pregnancy, haemoglobin concentration fell from a mean of 12-23 g/dl in early pregnancy to 11-04 g/dl at 34 weeks gestation, a level which was maintained until term. In the 153 women to whom iron supplements were given during pregnancy, the initial fall in haemoglobin concentration was less, was arrested by 28 weeks gestation and then rose to a level equivalent to the booking level. This different pattern in iron supplemented pregnancies was due to an increase in the red cell count together with a change in mean cell volume. Although the changed mean cell volume usually remained within the normal range in the group who did not take iron, a few women developed microcytosis which could reflect iron deficiency; a macrocytic change was noted in a small number of the women who received routine iron supplements and this could reflect iron "over sufficiency". The results are discussed in relation to the possible effects of giving routine oral iron to all pregnant women.

Red cell size as measured by the Coulter model S

The MCV (mean corpuscular volume) was examined by the Coulter model S. It was found that the MCV measured by the Coulter S was larger than the generally accepted range 82 to 92, or 76 to 96 mu(3). The range in 500 healthy individuals was 82.2 to 100.6 mu(3). It was also found that the mean MCV became larger with increasing age. No sex difference was found. The low MCV by manual methods was generally thought to be attributed to less accurate measurement of erythrocyte counts.