Posts

Venereal Disease Research Laboratory

Image
  VDRL (Venereal Disease Research Laboratory) Test Definition The VDRL Test is a non-treponemal serological test used to screen for syphilis, a sexually transmitted infection caused by Treponema pallidum. It detects reagin antibodies produced in response to cellular damage caused by the infection, rather than antibodies against the bacterium itself. Principle The VDRL test is based on a flocculation reaction. When a patient's serum containing reagin antibodies is mixed with a cardiolipin-lecithin-cholesterol antigen, visible clumping (flocculation) occurs if the test is positive. Objectives 1. To screen for syphilis infection. 2. To aid in the diagnosis of syphilis. 3. To monitor the effectiveness of syphilis treatment. 4. To detect congenital syphilis in appropriate clinical settings. 5. To identify individuals who require confirmatory treponemal testing. Materials Required Patient serum sample VDRL antigen suspension VDRL test slide Mechanical rot...
Post a Comment
Read more

Blood Count Test (CBC)

Image
  1. Objective: The objective of this test was to determine the total number of red blood cells (RBCs), white blood cells (WBCs), and platelets, along with hemoglobin concentration, hematocrit, and other related indices in a blood sample. 2. Principle: The test was based on the automated or manual counting of blood cells using electrical impedance or microscopic methods. In the automated method, blood cells passed through an electric field and caused changes in resistance that were counted electronically. In manual methods, cells were visually counted using a hemocytometer. 3. Materials: EDTA anticoagulated whole blood sample Microscope slides and cover slips Hemocytometer (Neubauer chamber) RBC and WBC diluting fluids Hemoglobinometer (or automated analyzer) Pipettes Microscope Gloves and sterile lancet (for sample collection)   4. Procedure (Microscopic/Manual): The patient’s blood sample was ...
Post a Comment
Read more

Urine Culture

Image
   1. Objective To detect and identify  pathogenic bacteria  (or fungi) in  urine  and determine their  antibiotic susceptibility , especially in suspected  urinary tract infections (UTIs) . 2. Principle Urine is inoculated onto  differential and selective media  to isolate and identify  uro-pathogens  such as  E. coli ,  Klebsiella ,  Proteus , and  Enterococcus . A colony count is performed to assess the significance of bacterial growth, and susceptibility testing is carried out using methods like  Kirby-Bauer disc diffusion .   3. Materials Sterile  midstream urine sample Inoculating loop (1 µL or 10 µL calibrated) Culture media: Cystine Lactose Electrolyte Deficient (CLED) agar MacConkey agar Blood agar Incubator (35–37°C) Antibiotic discs (for sensitivity testing) Mueller-Hinton agar (for disc diffusion) PPE and sterile containers 4. Procedure Mix  the urine sample gently. Use a...
Post a Comment
Read more

Complement Fixation Test (CFT)

Image
   1. Objective The objective of the Complement Fixation Test (CFT) was to detect the presence of specific antibodies or antigens in a patient's serum by observing complement-mediated lysis of indicator red blood cells. 2. Principle The test was based on the ability of antigen–antibody complexes to fix complement. If the patient's serum contained specific antibodies, they formed a complex with the added antigen and fixed the complement. When sheep red blood cells (SRBCs) coated with anti-sheep RBC antibodies were added, no hemolysis occurred, indicating a  positive  result. If there were no antibodies, the complement remained free and lysed the indicator SRBCs, indicating a  negative  result. 3. Materials Used Patient serum (heat-inactivated) Known antigen Complement (usually guinea pig complement) Sheep red blood cells (SRBCs) Hemolysin (anti-sheep RBC antibodies) Controls (positive and negative) Incubator and water bath 4. Procedure The patient's serum wa...
Post a Comment
Read more

Platelet Aggregation Test

Image
   1. Objective The objective of this test was to evaluate the functionality of platelets by measuring their ability to aggregate in response to various agonists. 2. Principle The test was based on the principle that platelets, when exposed to aggregating agents (agonists), clump together. This aggregation caused a change in light transmission through platelet-rich plasma (PRP), which was measured by an aggregometer. A functional platelet population exhibited a characteristic response to each agonist. 3. Materials Used Patient’s citrated blood Centrifuge Platelet aggregometer Aggregating agents: ADP, collagen, epinephrine, arachidonic acid, ristocetin Cuvettes and stir bars Pipettes 4. Procedure Blood was collected in a citrate tube and centrifuged at low speed to obtain PRP. The remaining blood was centrifuged at higher speed to prepare platelet-poor plasma (PPP) for use as a blank. PRP was added into a cuvette with a magnetic stir bar and placed in the aggregometer. A known ...
Post a Comment
Read more

Cholera Test

Image
  1. Objective The objective of the test was to detect the presence of Vibrio cholerae, the bacterium responsible for cholera, in stool samples or rectal swabs, aiding in diagnosis and outbreak control. 2. Principle The test was based on isolating and identifying Vibrio cholerae using culture, microscopy, or rapid immunochromatographic test kits. Culture allowed confirmation, while rapid tests gave quicker preliminary results by detecting cholera antigen in stool. 3. Materials Depending on the method used: ✔ For Culture: • Fresh stool sample or rectal swab • Transport media (Cary-Blair) • Selective media (Thiosulfate Citrate Bile Salts Sucrose agar – TCBS) • Enrichment broth (Alkaline Peptone Water) • Microscope and staining reagents • Oxidase reagent • Biochemical test kits ✔ For Rapid Cholera Dipstick Test: • Stool sample • Cholera antigen rapid test cassette • Extraction buffer • Dropper • Timer Read more test 4. Procedure 🧪 A. Culture Method 1. Stool ...
Post a Comment
Read more

HIV test

Image
   1. Objective The objective of this test was to detect the presence of HIV (Human Immunodeficiency Virus) antibodies or antigens in a patient's blood or serum to screen for HIV infection. 2. Principle The test was based on the detection of HIV-specific antibodies (IgG, IgM) and/or p24 antigen using Enzyme-Linked Immunosorbent Assay (ELISA), Rapid Immunochromatographic Tests, or Western Blot. In some advanced cases, nucleic acid testing (NAT) was used for early detection. 3. Materials Used HIV Rapid Test Kit (e.g., Determine, Uni-Gold, First Response) Patient's blood or serum sample Buffer solution Micropipette and tips Timer Biohazard disposal 4. Procedure A drop of patient’s whole blood or serum was placed on the test device sample pad. Two drops of buffer solution were added. The sample was allowed to migrate across the test strip by capillary action. Results were read after 15–20 minutes. Control and test lines were observed to interpret the result. 5. Result Positive: ...
Post a Comment
Read more