SOP – Malaria Microscopy - NVBDCP

Quality Assurance of Malaria Diagnostic tests8.1.6 Precautions to be taken while collecting blood (See Chapter 6)8.1.7 Common faults in making blood filmsGood quality thick and thin blood smears are the basic requirement for excellent microscopy.A number of faults are observed to be common in making blood films. These can affect thelabeling, the staining or the examination, and sometimes more than one of these. Followingsare few common faults encountered while making blood films.8.1.7.1 Wrongly positioned blood filmsCare should be taken that the blood films are correctly sited on the slide. If they are not, itmay be difficult to examine the thick film. Also, portions of the films may even be rubbed offduring the staining or drying process.8.7.1.2 Excess bloodThick films made with excess blood, after staining, will appear dark blue in their background.There will be too many white blood cells per thick film field and these could obscure or coverup malaria parasites that are present. If the thin film is too thick, Red Blood Cells (RBC) willbe on top of one another and it will be impossible to examine them properly after fixation.8.1.7.3 Too little bloodIf too little blood is used to make the films, there will not be enough RBCs in the thick filmand thus, the examiner will not have sufficient fields for standard examination. Besides, thethin films may also be too small for use as a label. If labeled on what so ever little blood iscollected, there would not be enough blood film left for examination as well.8.1.7.4 Blood films spread on a greasy slideThe blood films will spread unevenly on a greasy slide, which makes examination verydifficult. Some of the thick film will probably come off the slide during the staining process.SOP – Malaria Microscopy© Copyright to Dte. NVBDCP Only. Any modification are prohibited