Electronic Theses and Dissertations (Masters)

Permanent URI for this collectionhttps://hdl.handle.net/10539/38221

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A laboratory based retrospective study of plasma cell myeloma in the public sector of South Africa from 2017 to 2019
(University of the Witwatersrand, Johannesburg, 2024) Wilding, Bradley Thomas; George, Jaya
Background Plasma cell myeloma is a haematological malignancy characterized by clonal proliferation of plasma cells. This malignancy is frequently associated with the production of a monoclonal protein in either serum and / or urine, referred to as an M protein, which is used as a screening test for patients. Patients are then further investigated to assess if they meet the International Myeloma Working Group (IMWG) diagnostic criteria for plasma cell myeloma. There is limited literature describing plasma cell myeloma in South Africa, particularly in people living with HIV. Objective The primary objective of this study was to describe plasma cell myeloma in patients diagnosed in the public sector of South Africa over a three-year period. The secondary objective was to compare demographic features (age, sex) and diagnostic criteria, between the myeloma patients living with HIV and the HIV negative myeloma patients. Methods A retrospective analysis was performed on data from 4518 patients who had a positive immunofixation on serum and / or urine from public sector hospitals, between 2017 and 2019. A total of 718 of the 4518 patients met the laboratory criteria for plasma cell myeloma and were included in the analysis. Demographics (age, sex) and laboratory investigations used in the diagnostic criteria for plasma cell myeloma were analysed and statistically compared across the different HIV status of patients. Results Plasma cell myeloma patients presented at a mean age of 59.46 years with a female to male ratio of 1.2:1. In the patients that met the diagnostic criteria the most common end-organ damage present was anaemia in 77.16% patients and the most common biomarker of malignancy was a bone marrow trephine biopsy plasma cell percentage t60% in 55.71% patients. IgG isotype was the most common paraprotein detected on serum immunofixation in 58.5% of the patients. Kappa was the most common Bence-Jones protein detected in 27.16% of patients which was 1.76 times more common than lambda Bence-Jones protein. People living with HIV were younger 55.11 (±9.79) as compared to their HIV negative counterparts (p value 0.010). No other statistically significant difference was noted when comparing HIV status groups Conclusion In conclusion, this study described the demographics, laboratory investigations and diagnostic features of plasma cell myeloma patients diagnosed in the South African public sector from 2017 to 2019. We found that people living with HIV were diagnosed at younger age when compared to their HIV negative counterparts
Validation of Roche immunoassay for severe acute respiratory virus 2/SARS-COV-2 in South Africa
(University of the Witwatersrand, Johannesburg, 2023-01) Grove, Jurette Simone; George, Jaya; Mayne, Elizabeth
Background: Serology testing is an important ancillary diagnostic to the reverse transcriptase polymerase chain reaction (RT-PCR) test for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We aimed to evaluate the performance of the Roche Elecsys™ chemiluminescent immunoassay (Rotkreuz, Switzerland), that detects antibodies against the SARS-CoV-2 nucleocapsid antigen, at an academic laboratory in South Africa. Methods: Serum samples were collected from 312 donors with confirmed positive SARS CoV-2 RT-PCR tests, with approval from a large university’s human research ethics committee. Negative controls included samples stored prior to December 2019 and from patients who tested negative for SARS-CoV-2 on RT-PCR and were confirmed negative using multiple serology methods (n = 124). Samples were stored at –80 °C and analysed on a Roche cobas™ 602 autoanalyser. Results: Compared with RT-PCR, our evaluation revealed a specificity of 100% and overall sensitivity of 65.1%. The sensitivity in individuals > 14 days’ post-diagnosis was 72.6%, with the highest sensitivity 31–50 days’ post-diagnosis at 88.6%. Results were also compared with in-house serology tests that showed high agreement in majority of categories. Conclusions: The sensitivity at all-time points post-diagnosis was lower than reported in other studies, but sensitivity in appropriate cohorts approached 90% with a high specificity. The lower sensitivity at earlier time points or in individuals without symptomatology may indicate failure to produce antibodies, which was further supported by the comparison against in-house serology tests.