The diagnosis of microcytic anemia by a rule-based expert system using VP-Expert.

We describe our experience in creating a rule-based expert system for the interpretation of microcytic anemia using the expert system development tool, VP-Expert, running on an IBM personal computer. VP-Expert processes data (complete blood cell count results, age, and sex) according to a set of user-written logic rules (our program) to reach conclusions as to the following causes of microcytic anemia: alpha- and beta-thalassemia trait, iron deficiency, and anemia of chronic disease. Our expert system was tested using previously interpreted complete blood cell count data. In most instances, there was good agreement between the expert system and its pathologist-author, but many discrepancies were found in the interpretation of anemia of chronic disease. We conclude that VP-Expert has a useful level of power and flexibility, yet is simple enough that individuals with modest programming experience can create their own expert systems. Limitations of such expert systems are discussed.

Hereditary sideroblastic anaemia and autosomal inheritance of erythrocyte dimorphism in a Dutch family.

Size distribution curves of red blood cells were used to detect the presence of microcytes in peripheral blood of members of a Dutch family with hereditary sideroblastic anaemia. 22 of 49 members of this family have a bimodal erythrocyte volume distribution curve and a dimorphic blood picture. The pattern of inheritance of this morphological abnormality is clearly autosomal. It is suggested that the study of red blood cell size distribution curves may add valuable information on the pattern of inheritance in other families with hereditary sideroblastic anaemia.

Validade da estimativa da eritometria a partir do valor hematócrito / Validity of erythrocytometry based on hematocrit value

Este experimento foi baseado nos resultados de hemogramas completos em 112 amostras de sangue. As amostras foram obtidas de pessoas escolhidas ao acaso. O propósito foi o de comparar os resultados das eritrometrias determinadas em câmara de Neubauer com os resultados obtidos através do uso de índices de conversäo, os quais permitem a avaliaçäo do número de hemáceas por mm3 baseados no valor do micro hematócrito. Os resultados mostraram que para um nível de micro hematócrito entre 30% e 50%, o índice 103.630 agora proposto é o que apresenta a melhor correlaçäo, quando o objetivo é calcular a eritrometria baseada no valor hematócrito, desde que a hematoscopia revele eritrócitos normais tanto em forma como em tamanho

Combined use of zinc protoporphyrin (ZPP), mean corpuscular volume and haemoglobin measurements for classifying microcytic RBC disorders in children and young adults.

The diagnostic potential of the combined use of zinc-protoporphyrin (ZPP), mean corpuscular volume (MCV) and haemoglobin measurements for discriminating between iron deficiency anaemia, beta-thalassaemia minor and lead poisoning has been studied. Lead poisoning could be identified by ZPP greater than 50 micrograms/dl in the presence of normal MCV or ZPP greater than 150 micrograms/dl in the presence of microcytosis (MCV less than 80 fl) with a sensitivity of 97% and specificity 94%. Beta-thalassaemia minor was identified by the coexistence of microcytosis and ZPP less than 50 micrograms/dl with a sensitivity of 91% and specificity 79%. Iron deficiency anaemia defined by the combination of microcytosis and ZPP ranging from 50 to 150 micrograms/dl was identified with a sensitivity of 95%, but the specificity was only 51%, with many of the patients overlapping with thalassaemia minor. This problem did not exist in iron-deficiency anaemia with haemoglobin less than 10 g/dl as at that range no patients with uncomplicated thalassaemia minor have been encountered. A great advantage of the combined use of ZPP, MCV and haemoglobin for the initial screening of microcytic anaemia is its ease of performance and low cost. However, this information should only be regarded as presumptive evidence of disease, requiring subsequent confirmation by appropriate direct measurements such as transferrin saturation, serum ferritin, haemoglobin electrophoresis, or blood lead determinations.

[Must we teach, today, the MCHC (Mean Corpuscular Haemoglobin Concentration)? (author's transl)]. / Doit-on, en 1979, enseigner encore la CHCM (Concentration en Hémoglobine Cellulaire Moyenne)?

Automatic cell counters introduce a new interpretation of the MCHC. The automatic MCHC does not fall in cases of thalassemia or of iron deficiency, except in the severest; so it serves now little practical purpose. The manual MCHC continues to be a useful index of hypochromia, but does not reflect the true haemoglobin concentration in red cells, and it remains less and less in use.

Engraftment of bone marrow transplants in W anemic mice measured by electronic determination of the red blood cell size profile.

Defective stem cells of WBB6F1-W/Wv mice produce macrocytic red blood cells (RBCs); stem cells of WBB6F1-+/+ mice produce normocytic RBCs. Utilization of the Coulter counter channelyzer permitted good dissociation between the size distribution of populations of +/+ and W/Wv RBCs. Peaks (mean cell volumes) for +/+ and W/Wv RBCs have been determined to be between the 30th and 40th channel and 50th and 60th channel, respectively. Variability of profiles for individual mice of both genotypes did not exceed the variability of separate determinations of the same cell suspension from a single mouse. Admixture (approximately 15%) of either type of erythrocytes could be quantitatively detected by this method. One week after transplant of 10(7) +/+ marrow cells into W/Wv recipients, 25% of donor type erythrocytes were detected. Eighteen days post-graft, concentration of +/- normocytes exceeded the concentration of macrocytes in the W/Wv recipients' circulation. Approximately 45 days post-transplant, the proportion of macrocytes decreased below the 10% detectable level. Calculation of the daily RBC production rate during repopulation and estimation of the number of RBCs produced by a single hematopoietic colony were determined. The RBC size profile was found to be a convenient method for studying the effect of implantation of W/Wv marrow into lethally irradiated +/+ mice. This method proved suitable for repetitive determination of the size population in individual transplanted mice.