How long should a sample typically be spun in a centrifuge during stool flotation?

In stool flotation procedures, the typical centrifugation time is around 5 minutes. This duration is optimal for effectively separating and concentrating the parasitic elements from the fecal matter. In a flotation procedure, the suspension of stool is placed in a solution where lighter particles, such as protozoan or helminth eggs, will float to the surface when centrifuged.

Spinning for about 5 minutes allows for adequate sedimentation and separation without compromising the integrity of the sample or causing excessive damage to delicate eggs and cysts. If the centrifuge runs for shorter periods, there may not be sufficient separation, leading to inaccurate or incomplete results. Conversely, longer centrifugation times can result in the sediment being overly compacted, which may make it more difficult to analyze the sample effectively after flotation.

Ultimately, the choice of 5 minutes aligns with established protocols that aim to balance efficiency and sample integrity in parasitology laboratories.