role of the clinical immunology laboratory in the diagnosis and monitoring of connective tissue diseases

Connective tissue diseases CTD are a group of autoimmune systemic diseases that can affect any organ-system in the body. The initial clinical presentations of these diseases overlap, not only with each other, but also with a wide range of other rheumatological and non-rheumatological disorders. Due to these reasons, clinicians depend heavily on the use of the clinical immunology laboratory for the diagnosis of CTD. A large number of tests exist in the laboratory for the investigation of CTD and each test can be performed by a number of different methods, each with its own limitations. Consequently, the significance of the results generated not only has to be interpreted in relation to the clinical picture, but also to the method used to generate the results. Moreover, within the laboratory, there is a hierarchical testing system for the investigation of CTD and if this system is used appropriately, in conjunction with the clinical picture, can result in the diagnosis/exclusion of CTD more efficiently and economically. In contrast, random use of the laboratory tests, combined with limited knowledge of the methods used to carry out these tests, can lead to delay or even misdiagnosis, as well as can lead to wastage of resources. In the following review, we have discussed the various tests that are used in the investigation of CTD, as well as the different methods used to carry out these tests, with the hope that such knowledge would lead to a more efficient and economical use of the clinical immunology laboratory in the investigation of CTD