There is increasing interest in the absolute lymphocyte count. This is partly driven by the need to obtain absolute values for lymphocyte subsets such as absolute CD4+ counts in human immunodeficiency virus (HIV)-infected persons. The absolute total lymphocyte count is usually determined in the routine hematology laboratory on a separate sample from the same patient specimen and then combined with percentage results from flow cytometry to obtain the absolute value of the lymphocyte subsets. We have studied analytic variability in the absolute lymphocyte determination and compared it to the variability of the total white blood count (WBC). In a series of 524 specimens, four different automated methods were compared to each other and to the traditional eye count differential. The automated methods were four widely used automated cell counters (Technicon H*1, TOA NE8000, Coulter STKS, and Abbott CD3000). The results indicate that analytic variability in the absolute lymphocyte counts, due, primarily, to method variability, is significant and is larger than the variability typically observed on interlaboratory trials of relative CD4 counts. These method biases cannot easily be reduced by calibration, since the cell classification algorithms are built-in features of the various cell counters. Analytic variability of the absolute lymphocyte counts was found to be 12.4% compared with analytic variability of only 4.9% for total WBC counts on the same samples. Our data suggest that more precise results would be obtained if flow cytometry results expressed each phenotype as a fraction of the leukocytes as well as total lymphocytes. Conversion to absolute values could then be accomplished through determination of the total WBC in the routine hematology laboratory.

The MAXM is a compact blood count and differential analyzer that appeals to both the space-limited, full-service laboratory and the large outpatient practice. The authors compared the performance of the Coulter MAXM to the larger Coulter STKS. Linearity and precision studies were comparable to the STKS. MAXM leukocyte differentials were closely correlated with STKS and manual readings, being excellent in the neutrophil, lymphocyte, and eosinophil categories but poorer on monocyte counts. Basophil counts did not correlate with STKS or manual counts. Analyzer suspect flagging was similar in both machines, with the MAXM exhibiting slightly reduced sensitivity and greater specificity. MAXM processing of a single sample requires twice the time. The MAXM functions well for a large office practice and as a backup for large medical laboratories but, because of its hands-on requirements and lack of speed, cannot replace the larger, more automated analyzers.

Peripheral blood samples from 48 untreated and 20 treated patients with disease entities that directly or indirectly affect hematopoiesis [dys-myelopoietic syndrome (DMS), refractory anemia with excess blasts (RAEB) or in transformation (RAEBIT), lymphoma, myeloma, acquired immunodeficiency syndrome (AIDS), and solid tumors with uninvolved bone marrow] were measured with the Technicon H-6000 automated hematology analyzer; this instrument provides a differential count on 10(4) white blood cells (WBC) effected by means of flow cytochemistry (peroxidase content) and volume (light scatter) discrimination. Cases with DMS and RAEB showed statistically significantly lower WBC counts than normal, whereas cases with lymphoma showed significantly higher values. No disease entity demonstrated changes in mean peroxidase activity (MPA) that were significantly different from normal, although all disease entities, including cases with solid tumors, showed significantly higher (two to severalfold) proportions of cells with high peroxidase (HPX) content, probably as a reflection of a disturbance of normal hemopoiesis with the emergence of younger granulocytic forms. All cases with paraleukemia (DMS, RAEB, and RAEBIT) showed significantly higher values of large unstained cells (LUC), whereas cases with lymphoma showed significantly lower LUC values. There were no statistically significant differences for any parameter (WBC counts, MPA, HPX, or LUC) among the paraleukemia subtypes. However, based on the displayed trends, a case presenting with dyserythropoiesis, relatively low WBC counts, abnormal HPX values, and LUC below 10% should be suspected for RAEB, whereas the presence of greater than 10% LUC and almost normal or even slightly elevated WBC counts should suggest a more accelerated phase of RAEB. Unless complicated by a leukemic phase, cases of lymphoma or myeloma did not display changes in any of the parameters analyzed by the H-6000. Similarly, patients with AIDS had no overt changes other than a trend to lower WBC counts with occasionally higher or lower absolute lymphocyte counts than normal. The peripheral blood of patients with solid tumors displayed a slight increase in HPX, suggesting an indirect effect on hemopoiesis since careful workup failed to demonstrate bone marrow involvement. Our data demonstrates that an H-6000 analysis has a role in the evaluation and follow-up of all these entities particularly to document leukemic transformation of either lymphoma, myeloma, or RAEB.

Summary Peripheral blood samples from 73 patients with chronic leukaemia were measured with the Technicon H‐6000 automated haematology analyser to provide flow cytochemical (peroxidase content) and volume (light scatter) discriminated scattergram patterns. For chronic granulocytic leukaemia (CGL). these patterns were so reproducible and distinct that they allowed an immediate diagnosis even without the benefit of microscopic examination, Relative and absolute basophilia was an invariable feature, and remained detected by the H‐6000 even when the patient was in haematologic and cytogenetic remission or progressed into blast crisis (BC). Meet patients in BC also demonstrated an inordinately high number oflarge unstained cells (LUC) and high proportions of ‘lymphocytes’(small blasts with no peroxidase content by visual inspection). Thus, for patients with CGL, LUC values above 10%, and/or steady increments in the proportion of ‘lymphocytes’, merit concern as these changes may herald an accelerated phase of disease.The scattergram pattern of untreated chronic lymphocytic leukaemia (CLL) showed a dense accumulation of data points within the lymphocytic ‘box’with a small cluster of granulocytic elements. Most patients also had a frankly abnormal proportion of LUC. Sixteen patients with CLL were compared for ratios of LUC to lymphocytes and stage of disease; patients with the most advanced stage (IV) had the highest, statistically significant values, than the patients with more benign disease. Thus, it is possible that follow up with this instrument of patients with CLL will also allow early detection of an impending prolymphocytoid transformation (accelerated phase) of this disease.

SummaryPeripheral blood samples from 118 patients with acute leukaemia (68 untreated; 50 treated) were measured with the Technicon H‐6000 automated haematology analyser. This instrument provides, in addition to measurements of the classical haematology parameters (i.e. cell counts, haemoglobin concentration, etc.), a differential count on 104 WBC effected by means of flow cytochemistry (peroxidase content) and volume (light scatter) discrimination. Disregarding RBC and platelet counts and their volume distribution profiles, the most important diagnostic parameters for leukaemic disease were the WBC count, the WBC differential count, and the proportions of large unstained cells (LUC) and high peroxidase (HPX) cells obtained by the automated differential count as well as the mean value of the WBC peroxidase content distribution (MPA). Granulocytic leukaemias had lower MPA than normal and lymphocytic leukaemias had MPA values above normal. M1 leukaemias were also characterized by large proportions of LUC and low fractions of HPX, while M2 leukaemias showed low LUC with high HPX. M3 leukaemias had low LUC and very high HPX. M4 leukaemias had large LUC and‘monocytic’components and a modest fraction of HPX. M5 leukaemias had very large numbers of LUC,‘monocytes’and‘lymphocytes’and a normal HPX. For M1 leukaemia, the presence of less than 7% LUC following induction treatment was related to morphological changes of normal cells induced by chemotherapy while LUC above 10% usually indicated unsuccessful induction associated with the presence of residual blasts. If treatment was successful, M2 and M3 leukaemias characteristically decreased their HPX population. All M4 leukaemias studied by us failed to enter remission and continued to display high proportions of HPX and LUC. Similarly, most M5 leukaemias had a poor response to treatment and always showed a very high proportion of LUC. Untreated lymphocytic leukaemias demonstrated high LUC, normal HPX and a high proportion of‘lymphocytes’. Hairy cell leukaemias showed almost equal proportions of‘lymphocytes’and LUC. Successful chemotherapy of all lymphoid leukaemia entities was associated with rapid decreases in LUC. slower decrements of‘lymphocytes’and moderate and transient increments in HPX. Thus, flow cytochemistry can assist not only in the segregation of acute leukaemias along with FAB classification with nonmorphologic criteria, but also in the follow up of patients with these diseases.

The National Committee for Clinical Laboratory Standards (NCCLS) has published a tentative standard for leukocyte differential counting, by means of which a manual or automated method for leukocyte differential counting can be compared with a manual reference method. The performance of the Technicon H6000 system was evaluated using the standard at Stamford and Overlook Hospitals. A total of 502 patient samples were analyzed: 315 from Overlook and 187 from Stamford. The H6000 system was found to be approximately four times more precise than the 200-cell manual reference method for each cell type. Correlation of the H6000 system with the manual method was good, with correlation coefficients of 0.98 for neutrophils and lymphocytes, 0.96 for eosinophils, 0.72 for monocytes, and 0.5 for basophils. The clinical sensitivity of the H6000 system, measured in terms of false normals and false abnormals, was similar to that of the manual reference method when measured against itself. There were no clinically significant discrepancies in results from the H6000 system, except for possibly one case where a patient was already on antibiotic therapy. The NCCLS standard was found to be a useful but rather complex and involved method for evaluating the performance of the H6000 system, the major problem being the amount of work needed to count manually the number of cells required for the manual reference method.

Correlations are reported for rats between the Lee Obesity Index and percent body fat. At weaning, rats were divided into 4 groups: supermarket diet and ovariectomy, supermarket diet and sham surgery, Lab Chow pellets and ovariectomy, and Lab Chow pellets and sham surgery. Four other groups received the treatments as adults. Eighteen and fifteen weeks later, respectively, the rats were measured for Onesity Index and were sacrificed for carcass analysis. The Obesity Index correlated well with percent body fat for animals made obese by diet; but it was not generally reliable for ovariectomized rats or for pellet fed sham operated controls. The Percent body fat also correlated well with body weight and with a simple weight/length ratio for rats made obese by diet. Thus, while the Obesity Index can reliably predict percent body fat, it may be no better at doing this than are some simpler measures.

Abstract A study of the isolated perfused pig liver has been made to assess function for hepatic assist and to provide baseline values for altering techniques in liver storage. In 23 analogous perfusions lasting 6 hours, pre- and post-perfusion tests of liver function were compared. These results suggest that during the perfusion period, cell-membrane integrity was maintained and that oxidative metabolism including gluconeogenesis was unimpaired. A rise in aspartate transaminase indicated some cellular damage and the fall in bile production was ascribed to altered solute load. Preliminary results from the J. S. Marais Surgical Laboratory suggest that there is good correlation between the biochemical assessment of liver vialbility and the capacity of the perfused liver to support life after transplantation into another animal. At this time, the latter procedure remains the ultimate test of liver function after perfusion.