Papanicolaou (PAP) Staining : Introduction, Principle, Procedure and Interpretation

Papanicolaou stain (also Papanicolaou’s stain or PAP stain) is the most important stain utilized in the practice of Cytopathology. It is a polychromatic stain containing multiple dyes to differentially stain various components of the cells. This technique was developed by George Papanicolaou, the father of Cytopathology. This method is used to differentiate cells in the […]

Zika Virus : Structure, Epidemiology, Pathogenesis, Symptoms, Laboratory Diagnosis and Prevention

The Zika virus (ZIKV) is a flavivirus related to Dengue, Yellow Fever virus, Japanese encephalitis virus and West Nile virus. It is responsible for mosquito-transmitted infection known as Zika fever or Zika disease. Zika Virus is commanding worldwide attention recently because researchers have found evidence that Zika may be linked to birth defects and neurological […]

Widal Test : Principle, Procedure, Result Interpretation and Limitations

Salmonella typhi and Salmonella paratyphi A, B and C cause enteric fever (typhoid and paratyphoid) in human. Laboratory diagnosis of enteric fever includes Blood culture, Stool Culture and Serological test. Widal test is a common agglutination test employed in the serological diagnosis of enteric fever. This test was developed by Georges Ferdinand Widal in 1896 […]

Wade-Fite Staining Technique For Mycobacterium leprae

The Wade-Fite staining technique is a less common special staining useful in Histopathology. It is the modification of Ziehl-Neelsen Staining Method to demonstrate Mycobacterium leprae in tissue sections, which is much less acid and alcohol fast than the tubercle bacilli. PRINCIPLE OF WADE-FITE STAIN Mycobacterium leprae in comparision to Mycobacterium tuberculosis are much less acid […]

Gram Staining : Principle, Procedure, Interpretation and Animation

The Gram staining technique is the most important and widely used microbiological differential staining technique. It was developed by Dr. Christian Gram in 1884, and categorizes bacteria according to their Gram character (Gram positive or Gram negative). In addition this stain also allows determination of cell morphology, size, and arrangement. It is typically the first […]

Auramine-Rhodamine Staining for AFB : Principle, Procedure, Reporting and Limitations

Smear microscopy is the simplest and quickest currently available procedure to detect Acid Fast Bacilli (AFB) in clinical specimens. Most common staning technique involve classic Ziehl-Neelsen (ZN) staining method or one of it’s variants. Now a days, these methods have been supplanted by more sensitive Auramine-Rhodamine Fluorescence staining technique, also called Truant method for acid-fast […]

Ziehl-Neelsen Stain (ZN-Stain) : Principle, Procedure, Reporting and Modifications

The Ziehl-Neelsen stain (ZN stain), also called the hot method of AFB staining, is a type of differential bacteriological stain used to identify acid-fast organisms, mainly Mycobacteria. Acid fast organisms are those which are capable of retaining the primary stain when treated with an acid (fast=holding capacity). Members of the Actinomycetes, genus Nocardia (N. brasiliensis […]

Erythrocyte Sedimentation Rate (ESR) : Principle, Methods of Determination and Clinical Significance

The erythrocyte sedimentation rate (ESR) is a common hematological test for nonspecific detection of inflammation that may be caused by infection, some cancers and certain autoimmune diseases. It can be defined as the rate at which Red Blood Cells (RBCs) sediment in a period of one hour. PRINCIPLE OF ESR When anticoagulated blood is allowed […]