What is ZN staining used for?

Ziehl–Neelsen staining is a bacteriological stain used to identify acid-fast organisms, mainly Mycobacteria.

What is ZN stain test?

Microscopic examination of clinical samples for acid-fast bacilli using the Ziehl-Neelsen (ZN) stain has been a standard diagnostic tool and is used globally for rapid TB diagnosis. Microscopy can detect 60\% to 70\% of culture-positive samples with a lower limit of detection of 5 × 103 organisms/mL.

How is ZN stain done?

The Ziehl Neelsen (ZN) method of staining acid fast bacilli has been in vogue for more than hundred years. In the ZN method [1], the basic fuchsin phenol dye is used hot there by melting the unsaponifiable waxy substance on the surface of the cell wall.

Why ZN staining is called acid-fast?

Mycobacterium and many Nocardia species are called acid-fast because during an acid-fast staining procedure they retain the primary dye carbol fuchsin despite decolorization with the powerful solvent acid-alcohol. Nearly all other genera of bacteria are nonacid-fast.

What stain is used for Mycobacterium tuberculosis?

Acid-Fast Bacteria—Ziehl– Neelsen Stain This stain is used to identify Mycobacterium tuberculosis, the causative agent of tuberculosis.

Which bacteria Cannot stain by conventional ZN staining?

Thus, detection of minute numbers of acid-fast bacteria in tissue specimens is critical. The conventional ZN stain fails to identify mycobacteria in numbers less than 10(4) per ml. Hence many infections evade diagnosis.

Does AFB positive mean TB?

If your AFB culture was positive, it means you have active TB or another type of AFB infection. The culture can identify which type of infection you have. Once you have been diagnosed, your provider may order a “susceptibility test” on your sample.

What is critical step in the ZN staining?

The critical step of this staining process is the decolorizing step, which can be influenced by the thickness of the specimen smear. In addition, a fresh solution of hydrochloric acid in ethanol is highly reac- tive, meaning that the result should be evaluated with caution.

What is modified Zn stain?

The Modified Ziehl-Neelsen stain (mZN stain) is a type of differential bacteriological stain used to identify acid-fast organisms, mainly Mycobacteria. Oocysts of coccidian parasites, such as Cryptosporidium and Isospora, are also acid-fast. Hence they can also be detected and identified through mZN staining procedure.

What does AFB positive mean?

What is the mordant used in ZN staining?

Unlike the Ziehl–Neelsen stain (Z-N stain), the Kinyoun method of staining does not require heating. In the Ziehl–Neelsen stain, heat acts as a physical mordant while phenol (carbol of carbol fuschin) acts as the chemical mordant.

Which stain is used for the identification of tuberculosis except Zn stain?

Acid-Fast Bacteria—Ziehl– Neelsen Stain This stain is used to identify Mycobacterium tuberculosis, the causative agent of tuberculosis. Acid-fast organisms have a lipoid capsule that has a high molecular weight and is waxy at room temperature.