Automation in Haematology - Introduction to Hematology - Lecture Slides, Slides of Hematology

Download Automation in Haematology - Introduction to Hematology - Lecture Slides and more Slides Hematology in PDF only on Docsity! Automation in haematology Docsity.com Automated techniques of blood counting • Semi-automated instruments –Require some steps, as dilution of blood samples –Often measure only a small number of variables • Fully automated instruments –Require only that an appropriate blood sample is presented to the instrument. –They can measure 8-20 variables including some new parameters which do not have any equivalent in manual methods. Docsity.com Automated instruments • They have a high level of precision for cell counting and cell sizing greatly superior to that of the manual tech. • The results are generally accurate. • Aberrant results consequent on unusual characteristics of blood are “flagged” for subsequent review. Docsity.com Hb concentration – Hb is measured automatically by a modification of the manual (cyanide) method. – To reduce toxicity of Cyanide some systems replace it by a non-toxic material Na- lauryl sulphate. Docsity.com RBC count The RBCs are counted automatically by two methods ◦Aperture impedance: where cells are counted as they pass in a stream through an aperture. ◦Or by light scattering technology The precision of an electronic counting for RBCs is much better than the manual count, and it is available in a fraction of time. This made the use of RBC indices of more clinical relevance. Docsity.com Red cell distribution width (RDW) • Automated instruments produce volume distribution histograms which allow the presence of more than one population of cells to be appreciated.most instrument produce a quantitative measurement of variation in cell volume, an equivalent of the microscopic assessment of the degree of anisocytosis. This is known as the RDW. Docsity.com Total WBC count • The total WBC count is determined in whole blood in which red cells have been lysed. • Fully automated multichannel instruments perform WBC counting by either – Impedance – Or light scattering – Or both. Docsity.com Automated differential count • Automated differential counters which are available now generally use flow cytometry incorporated into a full blood counter rather than being standard alone differential counters • Automated counters provide a three-part or five- to seven-part differential count. Docsity.com Analysis may be dependant on: ◦ Volume of the cell ◦Other physical characteristics of the cells ◦ Sometimes the activity of cellular enzymes such as peroxidase.  technologies used ◦ Light scattering and absorbance ◦ Impedance measurement Automated differential counters employing flow cytometry classify far more cells than is possible with a manual differential count. Docsity.com • The accuracy of automated counters is less impressive than their precision. • In general automated differential counters are favourable to the manual in 2 conditions – Exam of normal blood samples – Flagging of abnormal samples Docsity.com Platelet count • Platelets can be counted in whole blood using the same tech. Of electrical or electro-optical detection as are employed for RBCs. • Other parameters include – MPV – PDW – Plateletcrit= MPV x platelet count. Docsity.com