From: Impact of a training course on the quality of malaria diagnosis by microscopy in Angola
Classification | Criteria | |
---|---|---|
Thick blood smear | Thin blood smear | |
Bad | - Smear too big (diameter greater than 1 cm) or too small (diameter less than 0.5 cm); | - Smear too big (more than half of the slide) or too small (smaller than 0.5 cm); |
- Smear very close from the edge of the slide (less than 1 cm) which enables the use of immersion oil; | - Smear spread unevenly with patchy distribution, streaky and with many tails (greasy slides or edge of the spreader slide chipped); | |
- Very thick smear (fine print cannot be read through it); | - Very thick smear that fine print cannot be read through it or too thin with few red blood cells; | |
- Poorly stained (red blood cells are not lysed and parasites have a green, red, or blue colour). | - Many red blood cells lysed and lightly stained cells (red and white blood cells) and parasites. | |
Satisfactory | Smear well-made regarding size and location but moderately stained (red blood cells are partially lysed and parasites are lightly stained). | Smear well-made regarding size and location but moderately stained (red blood cells are partially lysed and parasites are lightly stained). |
Good | - Smear round in shape with a diameter of approximately 1 cm; | - Smear with the right dimension (half of the slide leaving space for thick blood); |
- Smear at least 1 cm away from the edge of the slide; | - Smear spread evenly (without patchy or streaky distribution); | |
- Smear density that fine print can be read through it; | - Smear density that fine print can just be read through it; | |
- Smear with all of the red blood cells lysed, and the malaria parasites are well-exposed with a bluish pink coloration. | - Smear with intact red blood cells and pink coloration, intact white blood cells properly stained, and malaria parasites are well-exposed with a bluish pink coloration. |