Clinical and laboratory haematology最新文献

Seasonal changes in red cell parameters need to be defined in order to properly interpret laboratory results. In this study blood counts were obtained prospectively in 104 healthy men (84 non-smokers and 20 smokers) aged 28-63 years during the summer and winter months. Seasonal changes in plasma volume were also calculated. In healthy non-smokers, their haemoglobin concentration and haematocrit ratio were lower in summer than in winter with a concomitant 5.5% increase in plasma volume. In smokers, there was no change in plasma volume, but haematocrit levels increased in summer. We conclude that both smoking status and seasonal variation should be taken into account in the evaluation of blood count results. Further studies are warranted to determine if our results can be extrapolated to subjects of both sexes and of various ages exposed to different climatic conditions.

The introduction of automation for haemoglobinopathy screening is an important advance in technology for haematology laboratories. This paper evaluates the utility of an automated HPLC instrument, the Bio-Rad 'Variant' for the detection and quantitation of the normal haemoglobins (Hb A, A2 and F) and the common abnormal haemoglobins (Hb S, C, DPunjab, E, OArab and Lepore) which need to be evaluated in laboratories undertaking carrier and/or neonatal screening for sickle cell and thalassaemia. The instrument only uses a small amount of whole blood (5 microliters), a 3 mm disc from a Guthrie spot may also be used for analysis of samples from neonates. It uses a 100 place automatic sampler with a cycle time of 6.5 min for adult samples (using the 'Beta Thalassaemia Short' reagent pack) and 3 min for neonatal samples. The automatic sampler also allows samples to be analysed 'out of hours'. A 'STAT'; position allows urgent samples to be analysed before, or during, a routine analytical run. All reagents, other consumables and application notes are provided by the suppliers. Other types of reagent packs, such as the 'Sickle Cell Short' for neonatal screening were not assessed during this study.

Results from the Sysmex SF-3000 automated haematology analyser are reported with special attention to leucocyte morphology flagging in pathological conditions. Results for leucocyte differential counts provided by the Sysmex SF-3000 were compared with those obtained from the Sysmex NE-8000 and a visual evaluation based on a differential count of 400 leucocytes. One hundred samples from apparently healthy subjects and 100 samples from patients with haematological abnormalities were examined. The SF-3000 yielded a rather high frequency of flagging inappropriately referring to blasts, immature granulocytes, left shift and nucleated red blood cells/platelet clumps. The presence of atypical lymphocytes was not indicated by appropriate flagging.

The thalassaemias are a heterogeneous group of genetic haemoglobin disorders. The use of the Sysmex R- 1000 instrument in their study during the last 5 years has proved valuable. 1 Reticulocyte percentage and absolute counts were estimated in heterozygous beta-thalassaemia, in beta thalassaemia intermedia and in sickle beta thalassaemia and were compared with normal controls. Reticulocyte maturation subpopulations (high, middle and low fluorescence ratio) were assessed and compared with those of other haematological disorders. Red cell size and non-specific auramine-O binding were shown to be factors affecting mature red cell autofluorescence. 2 Nucleated red blood cells (NRBC) interfere with leucocyte counts in most haematology analysers. The upper particle count (UPP), provided by the R-1000 with modified fluorescence amplification voltage, appeared to produce a direct NRBC count in beta-thalassaemia intermedia when compared to NRBC counts assessed indirectly. 3 Erroneous platelet counts are reported by most haematology analysers in thalassaemia intermedia (especially in haemoglobin H disease) due to extensive microcyte-platelet interference and cause problems in diagnosis and management. Platelet counts provided by the R-1000 instrument in such patients were comparable to counts assessed by microscopy. Flow cytometric analysis by the Sysmex R-1000 instrument is useful in thalassaemia syndromes not only for providing precise reticulocyte counts and reticulocyte maturation data, but for direct NRBC counting and accurate platelet enumeration in cases of thalassaemia intermedia.

The widespread use of intensive therapies and the need to haematologically monitor patients on a frequent basis means that the proportion of blood samples with moderate to severe leucopenia is significant and increasing. From a laboratory perspective, particularly because of the need to spend significant amounts of time in obtaining manual differentials from stained smears with low leucocyte numbers, these clinical trends have created additional pressures on what is often a limited manpower resource. Moreover in such situations, differentials obtained from examination of only 20 or 50 cells are not uncommon and the statistical consequences of this will be clearly apparent. Currently, there is general user confidence for automated leucocyte differentials for blood samples with normal WBC parameters, but there has been some reluctance to extend this to samples with leucopenia. In order to explore this further, we examined the efficiency of a modern automated five-part differential analyser (Abbott CELL-DYN 3500) in an unselected series of 292 samples with leucopenia (WBC count range range; 0.28-2.48 x 10(9)/l). Of these, 49 were from leucopenic sero-positive HIV patients with the remaining 243 samples originating from haematological oncology clinics, patients receiving radiotherapy for non-haemopoietic malignancies, and from patients with various chronic diseases. Morphologically, 204 of these samples did not show any blast cells or NRBC, 48 had blast cells but no NRBC, 29 had NRBC but no blasts, and the remaining 11 showed both blasts and NRBC. For 277 cases with less than 5% blasts, there was an excellent correlation between the manual and CD3500 automated differential, with no obvious bias between manual and automated subpopulation estimates at any percentage level. Linear regression analyses comparing absolute neutrophil, eosinophil, lymphocyte and monocyte counts for these same samples further revealed impressive correlations (r > 0.92) for all leucocyte populations and the absolute neutrophil count in particular (r = 0.986). Manual and CD3500 leucocyte differential comparisons for 11 cases with > 5% blasts showed good correlations for absolute neutrophil and eosinophil counts although, when the blast cell percentage was high, correlations for lymphocyte and monocyte counts were less consistent (an operator alert in the form of a 'Blast Flag' was, however, given in 10/11 of these particular cases). Four additional cases where manual differentiation between lymphoid cells and monocytes was recorded as difficult also showed consistently good correlations for manual vs automated neutrophil and eosinophil estimates. Not surprisingly, and essentially as a result of the low confidence noted for the manual differential itself, correlations for lymphoid and monocytic cells were relatively poor. In conclusion, this study has demonstrated that the CD3500 provides reliable and accurate absolute neutrophil and eosinophil counts in leucopenic samples

We investigated a flow cytometric method with monoclonal antibody CD42a as a potential reference method for platelet enumeration by blood count analysers. Using peripheral blood samples from 25 healthy individuals we obtained significant (P < 0.0001) correlations between the results obtained by a FACScan method and similar cell counters (TOA Medical Electronics, Kobe, Japan): r = 0.960 (FACScan vs SSF), r = 0.958 (FACScan vs SE-9000A,B), r = 0.949 (FACScan vs K-4500A) and r = 0.954 (FACScan vs K-4500B). This flow cytometric method for counting platelets using the monoclonal antibody CD42a can be used to check the calibration of the platelet count by blood cell analysers.

Healthy reference ranges for the total peripheral reticulocyte count and its three subpopulations, LFR (low fluorescence ratio), MFR (middle fluorescence ratio) and HFR (high fluorescence ratio) were established on 1219 healthy subjects. Samples were taken from subjects of both sexes with ages ranging from 4 to over 60 years. The observed ranges were found to be different between males and females for the group over 20 years old, while there was no difference between sexes found at the age between 4 and 19 years.

This study was undertaken in 102 adult patients to evaluate the safety and efficacy of intravenous (i.v.) midazolam in the setting of bone marrow aspiration and trephine biopsy (BMAT). Combined local anaesthetic (LA) and sedation was used in 87% of patients and 13% received LA alone. Amnesia occurred in all sedated patients with only 9% experiencing a mild degree of post-procedure pain. This contrasted sharply with the non-sedated group, in whom 85% had intense pain during the biopsy followed by protracted local discomfort in approximately 54%. Drowsiness and some psychomotor impairment were the only notable sedation-related side-effects in approximately 20%. None required assisted ventilation. There was a resounding patient preference for BMAT with sedation. Considering the ease of use, safety and efficacy of i.v. midazolam, the availability of flumazenil as a reversal agent and the undoubted positive effects on quality of life, we would advocate using it in BMAT provided that there were no contraindications.