Clinical Laboratory Training - Serological Tests PDF

Clinical Laboratory Training Serological tests College of Pharmacy, University of Al-Zahraa. Fifth year/First Semester Lec.7: by Dr. Iman Hussein Naser  Serology *The branch of laboratory medicine that studied blood serum for evidence of infection and other parameters by...

Clinical Laboratory Training Serological tests College of Pharmacy, University of Al-Zahraa. Fifth year/First Semester Lec.7: by Dr. Iman Hussein Naser  Serology *The branch of laboratory medicine that studied blood serum for evidence of infection and other parameters by evaluating antigen- antibody reaction in vitro. *The term usually refers to the diagnostic identification of antibody in the serum. Could we detect antigen too?  Study antigen-antibody reaction that useful in the diagnosis of disease, blood grouping ….  Antigen any substance can stimulate and react with an immune response that could be part or whole the substance/ microorganism.  Antibody protein is produced by the immune system in response to antigen and is of 5 groups (IgA, IgM, IgD, IgE, IgG). Terms used to evaluate test methodology Sensitivity: 1. Analytical sensitivity: ability of the test to detect very small amount of a substance. 2. Clinical sensitivity: ability of the test to give positive results even when the patients have other diseases Specificity: 1. Analytical specificity: Ability of the test to detect substance without interference from cross-reacting substance. 2. Clinical specificity: ability of the test to give negative result if patients doesnot have disease (no false positive result) Serological test for Syphilis detection: (VDRL) test Syphilis is a venereal disease caused by Treponema Palldium spirochete, the disease progress for several years if untreated. Two tests are used for the detection of syphilis 1.Venereal disease research laboratory (VDRL) 2. Rapid Plasma Reagin Card test (RPR) Both tests must be ordered to confirm the diagnosis of the disease  Venereal disease research laboratory (VDRL) The test depends on the detection antibody in the serum or CSF of the patients with syphilis disease, the solution used in the detection is a colorless alcoholic solution contain cardiolipin antigen isolated from cows hearts (di phosphatidyl glycerol) that form flocculation with antibody. -The blood test must be ordered after 4-6 weeks of infection which is the time for antigen in the blood to be developed. The test is highly sensitive ( show few negative results), the test shows low specificity (false positive occur with malaria, leprosy, typhus fever, measles, rheumatoid arthritis, scarlet fever, pregnancy. Rapid Plasma Reagin Card test -The RPR test measures IgM and IgG antibodies to lipoidal material released from damaged host cells as well as to lipoprotein-like material, and possibly cardiolipin released from the treponemes. *The reagent used is the same for the VDRL test with little modification. *The tests were ordered before marriage, during the first prenatal checkup for the pregnant woman. *The untreated condition results in abortion, stillbirth, pre- mature labor, the effect on fetus result in CNS.damage, hearing loss, and possible death VDRL Test RPR-Test  ASO-Titer ASO-Titer: a blood test to measure antibodies against streptolysin O, a substance produced by group A streptococcus bacteria. Antibodies are proteins our bodies produce when they detect harmful substances, such as bacteria. The ASO antibody may be found in the blood weeks or months after the strep infection has gone away. Why the Test is Performed You will need the test if you have symptoms of a previous infection by group A streptococcus. Some illnesses caused by these bacteria are: Bacterial endocarditis, an infection of the inner lining of your heart Guttate psoriasis A kidney problem called glomerulonephritis Rheumatic fever, which can affect the heart, joints, or bones Scarlet fever Strep throat ASO- Normal Value Adult value (