Using the laboratory : a handbook for medical practitioners / prepared on the advice of the Standing Medical Advisory Committee and the Central Pathology Committee.

  • Great Britain. Standing Medical Advisory Committee.
Date:
[1971]
Catalogue details

Licence: Open Government Licence

Credit: Using the laboratory : a handbook for medical practitioners / prepared on the advice of the Standing Medical Advisory Committee and the Central Pathology Committee. Source: Wellcome Collection.

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    4.3 4.3.1 In routine use the lowest possible incidence of false positive results is desirable, and methods are selected for this purpose—even though an occasional false negative may occur. However, in some cases only low levels of gonadotrophins are excreted (eg. ectopic pregnancy) and the Pathologist should be informed if this sabe sain is suspected so that a more sensitive test can be used. Protein, blood, and bacteria can interfere with some tests, giving false positive results. Positive pregnancy tests are found alsoin women with hydatiform mole and chorionepithelioma. In men with teratoma or seminoma of the testis such tests are also positive and if these are suspected this should be indicated to the Pathologist. Tests for Rheumatoid Factors Two tests for the detection of serum rheumatoid factors are available in special departments : 5ml of blood in a dry sterile container (Code White) is required. Both of these tests depend upon demonstrating in the patient’s serum the presence of antibodies against immunoglo- bulins. Sheep Cell Agglutination Test (Rose-Waaler) This test detects antibodies against rabbit gamma globulin on sheep red cells and itis positive in 70% of patients with definite rheumatoid arthritis. lt may also be positive in systemic lupus erythematosus. High titres are often found in the presence of rheumatoid nodules