Which technique is a direct smear used for detection of parasites?

Which technique is a direct smear used for detection of parasites?

• A. Fecal flotation
• B. Direct smear
• C. Intravenous injection
• D. Urinalysis

Answer: (C)

Direct smear is a simple microscopic method used to detect parasites by examining a sample directly, without extensive processing. For stool, a small amount is placed on a slide with saline or iodine, coverslipped, and looked at under a microscope to find motile trophozoites (like Giardia) or parasite cysts that may be present. It’s fast and requires minimal prep, which makes it useful for quick detection, especially when parasites are present in higher numbers or when observing motility helps identification. However, it’s less sensitive than concentration techniques for finding eggs or oocysts, which is why methods that rely on flotation or sedimentation are often used in parallel. Intravenous injection isn’t a diagnostic smear and isn’t used to detect parasites, and urinalysis examines urine contents for clues of disease or infection but isn’t a direct smear technique for parasite detection in stool.

Direct smear is a simple microscopic method used to detect parasites by examining a sample directly, without extensive processing. For stool, a small amount is placed on a slide with saline or iodine, coverslipped, and looked at under a microscope to find motile trophozoites (like Giardia) or parasite cysts that may be present. It’s fast and requires minimal prep, which makes it useful for quick detection, especially when parasites are present in higher numbers or when observing motility helps identification. However, it’s less sensitive than concentration techniques for finding eggs or oocysts, which is why methods that rely on flotation or sedimentation are often used in parallel. Intravenous injection isn’t a diagnostic smear and isn’t used to detect parasites, and urinalysis examines urine contents for clues of disease or infection but isn’t a direct smear technique for parasite detection in stool.