Indole Test : principle, procedure and interpretation

Indole test is the a biochemical test performed on bacterial species to detect the ability of an organism to degrade the amino acid tryptophan and produce indole. It is used as the part of the IMViC tests, a set of four useful reactions that are commonly designed for the differentiation of enterics (members of family […]

Complement Fixation Test : principle, procedure and interpretation

The complete fixation test (CFT) is used to detect the presence of specific antibodies in the patient’s serum. This test is based on the use of complement, a Biologically labile serum factor that causes the immune cytolysis i.e. lysis of antibody coated cells. Principle of complement fixation test It is the nature of the complement […]

Various shapes and arrangements of Bacterial cells

Bacteria are the ubiquitous microscopic organisms that are not visible with the naked eye. Bacterial morphology (size, shape and arrangement of bacterial cells) is one of the mostly used feature for the differentiation of various bacterial species. However pleomorphic bacteria can assume several shapes, following are the three basic bacterial shapes: Coccus (plural-cocci) : spherical […]

Germ Tube Test for the identification of Candida albicans

The Germ Tube Test, also known as Reynold’s Brande phenomena is a screening procedure which is used for the identification and differentiation of Candida albicans from other yeasts. Principle of the Germ Tube Test This test allows the detection of the Germ Tubes which are the initial stage of hyphae formation. These are the short, […]

Periodic Acid Schiff (PAS) Staining Technique For Carbohydrates

Periodic Acid Schiff (PAS) staining is one of the most commonly performed special staining technique in histopathology laboratory which is used to highlight molecules with high percentage of carbohydrate content such as mucin, glycogen, fungi and basement membrane in skin. Principle of PAS Staining PAS method works by exposing the tissue to periodic acid. Periodic […]

Common blood collection tubes, their additives and laboratory uses

The evacuated tube system for blood collection in use for various laboratory tests consists of tubes of various sizes, with color coded tops indicating tube contents. Most blood collection tubes contain an additive that either accelerates clotting of the blood (clot activator) or prevents the blood from clotting (anticoagulant). The list below lists the most […]