Medical Technology SA - Volume 28, Issue 1, 2014
Volume 28, Issue 1, 2014
Source: Medical Technology SA 28 (2014)More Less
Author Carol MassynSource: Medical Technology SA 28 (2014)More Less
I am pleased to announce that the Medical Laboratory Professionals Congress 2015 (MLP 2015) will take place at the Boardwalk Convention Centre, Port Elizabeth, from 15 - 17 May 2014. This will be the 23rd Society of Medical Laboratory Technologists of South Africa (SMLTSA) National Congress.
Reducing unnecessary blood smear examinations : can Sysmex blood cell analysers help? : peer reviewed original articleSource: Medical Technology SA 28, pp 6 –12 (2014)More Less
Background The microscopic assessment of a peripheral blood smear is an essential diagnostic tool. Many haematology laboratories currently assess smears microscopically for every full blood count request, many of which may however be assessed unnecessarily - an important consideration in resource-constrained settings. Modern blood cell analysers are increasing in sophistication and can flag abnormal specimens that may require microscopy.
Objectives To evaluate the flagging efficiency of the Sysmex haematology analysers and to determine whether this potentially labour-saving technology could assist in safely reducing the number of unnecessary microscopic blood smear assessments.
Methods A total of 427 full blood count specimens collected consecutively over a 24-hour period at NHLS Pelonomi and NHLS Kimberley, were evaluated microscopically and compared with the instruments' abilities to flag potential morphological abnormalities.
Results The Sysmex blood cell analysers flagged 63.7% of specimens as "positive" and 36.3% as "negative". After microscopy, false positive flags were found to constitute 18.5% and false negative flags 5.4% of the total number of smears reviewed, giving a total of 23.9% incorrect assessments. No false negative flag was clinically critical.
Conclusion False negative results occurring with the Sysmex instruments' flagging systems in our settings are relevant, although not critical. The potential time and monetary savings of a flagging-based smear review policy may weigh heavier than occasional false negatives. In the African milieu, where laboratories are faced with the challenges posed by staff- and other shortages, relying on instrumentation flagging to guide smear review policy should be considered.
Author W.J. MauleSource: Medical Technology SA 28, pp 13 –19 (2014)More Less
First described in the 1940s, Waldenström Macroglobulinaemia (WM) over time has developed conceptually from a clinical syndrome to a definitive clinicopathological entity. Progress is being made in standardisation of the disease definition, the overall treatment response criteria and the role of the haematology laboratory in supporting the WM patient, although nosologic disputes persist. The World Health Organisation (WHO), for example, has defined WM as a lymphoplasmacytic lymphoma (LPL) associated with IgM monoclonal gammopathy and bone marrow involvement. The latest guidelines from the British Committee for Standards in Haematology, Royal College of Pathologists (BCSH) define WM as an LPL which is a slowly progressive, clonal disorder of mature B cells, with features of plasma cell differentiation. Paraproteinaemia (usually IgM) is common and may give rise to hyperviscosity. The clonal expansions of these post-germinal centre lymphoid cells express a number of immunophenotypic markers that include: CD19, CD20 and surface IgM. These markers along with a number of others can be used to aid diagnosis. Disease symptoms are often divided into those related to tumour infiltration and those related to the effects of the monoclonal IgM. As with the other low-grade lymphomas, asymptomatic patients are observed only, with treatment reserved for those symptomatic patients. WM is a rare disorder that only comprises around 2% of all haematological malignancies. The haematology laboratory's role in diagnosis and monitoring the disease has grown over the years and this is best understood by examining the pathophysiology/biology, diagnosis and treatment of WM.
Physician satisfaction and emergency (stat) laboratory turnaround time during various developmental stages : peer reviewed original articleSource: Medical Technology SA 28, pp 20 –25 (2014)More Less
The aim of this study was to compare physicians' perceptions of turnaround time (TAT) with measured TATs for potassium and troponin T, (i) before installation of a pneumatic tube system (PTS), (ii) after installation of the PTS, and (iii) after installation of the automated chemistry analytical system (ACAS). Physicians were in general more satisfied with the TAT of the emergency (stat) laboratory after installation of the ACAS. This finding is in contrast with the TATs for potassium, which worsened significantly (p<0.0001) with each developmental stage, probably because of simultaneous installation of other point-of-care (POC) systems at strategic places. We concluded that our emergency test TAT deteriorated with each developmental stage and decided to update communication systems, introduce a stat line for fast registration of specimens, prioritise chemistry requests from various intensive care units, wards and hospitals, and appoint more pre-analytical staff. A follow-up study will be necessary to reveal whether these precautionary measures were successful or not.
Prevalence of abnormal bloodflow patterns and effects of biochemistry and lifestyle factors on the major neck vessels in patients with Multiple Sclerosis in the Western Cape, South Africa : peer reviewed original articleSource: Medical Technology SA 28, pp 26 –33 (2014)More Less
Objectives The purpose of this study was to investigate the prevalence of vascular dysfunction (chronic cerebrospinal venous insufficiency; CCSVI) and the effects of biochemical and lifestyle factors on carotid arteries and internal jugular veins (IJVs) in patients diagnosed with multiple sclerosis (MS).
Methods A B-Mode and Doppler ultrasound examination was done on 29 MS patients assessing the vasculature to identify patency, stenosis, occlusion and/or abnormal bloodflow patterns. Lifestyle (smoking, exercise and diet), Expanded Disability Status Scale (EDSS) and biochemistry (fibrinogen, plasma homocysteine and serum total cholesterol) data were available for 20 patients.
Results No evidence was found for CCSVI or deep vein thrombosis. Smokers displayed significantly smaller cross-sectional diameters of the proximal (p=0.03) and mid left IJV (p=0.02) than non-smokers. There was an inverse association (p=0.03) between physical activity and the intima media thickness (IMT) of the left common carotid artery (CCA). The EDSS showed a direct association with the IMT (p<0.0001) and an inverse association with adherence to a lifestyle/dietary program (p=0.03). Fibrinogen was associated with the peak systolic velocity of the left External Carotid Artery (p=0.03) and homocysteine showed an inverse association with the cross sectional diameter of the proximal left IJV (p=0.045). No significant associations were found between ultrasound measurements and total cholesterol.
Conclusions This pilot study supports previous findings that there is no association between CCSVI and MS, but rather a detrimental effect of smoking and a sedentary lifestyle on MS disability. This may indicate that people diagnosed with MS may improve their disability status by avoiding risk factors that would adversely affect the vasculature.
The effect of Tenofovir on renal function in HIV-positive patients in Lesotho : peer reviewed original articleSource: Medical Technology SA 28, pp 34 –38 (2014)More Less
Lesotho introduced tenofovir disoproxil fumarate (TDF) for first-line antiretroviral treatment (ART) in 2008. The use of TDF has been associated with renal toxicity. The study utilised an analytical design to compare retrospective creatinine clearance (CrCl) data of 312 antiretroviral treatment naïve adults exposed to TDF and 173 unexposed patients. Impaired renal function was defined as CrCl<50 ml/min calculated using the Cockcroft-Gault equation. In fifty-six patients (17.9%) TDF was found to be contraindicated. The use of TDF was marginally significant factor for renal toxicity (p=0.054) in univariate analysis, but was insignificant (p=0.122) in multivariate logistic analysis. Univariate (p<0.1) and multivariate logistic regression (p<0.05) were performed using STATA® 11. Female gender (p=0.016), hypertension (p=0.009), and age > 60 (p=0.004) were significantly associated with CrCl<50 ml/min outcome. TDF is a weak contributing factor to renal impairment. Routine baseline renal function screening should be adopted to prevent patients with impaired renal function receiving TDF.
Source: Medical Technology SA 28, pp 39 –40 (2014)More Less
In hospitalized patients, plasma sodium disturbances remain common and can be associated with significant mortality and morbidity if not diagnosed and treated. A hypoproteinaemic, critically ill patient with discrepant blood gas analyzer and central laboratory analyzer sodium values presented as a case of possible spurious elevation of sodium or pseudohypernatraemia. The indirect ion selective electrode method yielded a persistently higher sodium value than the direct ion selective electrode method. A statistically significant difference between the sodium measured with the direct ISE and indirect ISE method was noted. The differences could not be explained by analytical variation alone, in most of the samples.