Skip to main content

Table 1 Blood smears classification criteria (Adapted from Kiggundu et al.[15])

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.