Critical value reporting : A survey of 36 clinical laboratories in South Africa

KMObjective: Critical value policies are used by clinical laboratories to decide when to notify caregivers of life-threatening results. Despite their widespread use, critical value policies have not been published locally. A survey was designed to determine critical value policies for haematology tests in South Africa. Methods: A survey was carried out on 136 identified laboratories across South Africa in January 2013. Of these, 36 responded. Data collected included critical value policies, critical values for haematology parameters, and critical value reporting. Results: Of the 36 laboratories surveyed, 11.1% (n=4) were private, 33.3% (n=12) were affiliated to academic institutions and 55.6% (n=20) were peripheral or regional National Health Laboratory Service laboratories. All the laboratories confirmed that they had a critical value policy, and 83.3% of such policies were derived from local clinical opinion. Mean low and high critical limits for the most frequently listed tests were as follows: haemoglobin 20 g/dl, platelet count 1 000 ×109 /l, white cell count 46×109 /l, activated partial thromboplastin time >101 seconds, and international normalised ratio >6. In almost all cases critical value reporting was performed by the technologist on duty (97.2%). The majority of laboratories required that the person notified of the critical value be the doctor who ordered the test or the caregiver directly involved in the patient’s care (83.3%); 73.3% of laboratories indicated that they followed an algorithm if the doctor/caregiver could not be reached. Conclusion: Each laboratory is responsible for establishing clinically relevant critical limits. Clinicians should be involved in developing the laboratory’s critical value policy. The findings of this survey may be of value to local laboratories that are in the process of establishing or reviewing critical value policie

Point-of-care estimation of haemoglobin concentration in all age groups in clinical practice

Background: The measurement of haemoglobin (Hb) concentration provides a reliable, primary screening test for the presence and severity of anaemia. The HemoCue® is a point-of-care test for Hb measurement. The introduction of point-of-care testing in hospitals and general practice has improved patient care and accessibility. This study was performed to evaluate the utility of point-of-care Hb measurement with the HemoCue® device for the diagnosis of anaemia. Method: In this prospective study, we compared the analytical performance of the HemoCue® to the Coulter® LH 750 automated haematology analyser with regard to accuracy, precision and linearity in the measurement of Hb in adult and paediatric patient samples, referred for routine laboratory testing. Results: Samples from 100 patients were analysed with both instruments, and the results were compared using standard scatter and difference plots. The mean Hb value of the HemoCue® (11.3 g/dl; range 4.6-16.7) was comparable to the Coulter® LH 750 (11.3 g/dl; range 4.7-17.2). The Bland-Altman difference plot revealed good correlation. Bias between the two methods was small, and the imprecision was within acceptable limits. Hb measurement was linear in the range of 4.8-20 g/dl. Conclusion: In all age groups, the HemoCue® point-of-care device can be used to provide accurate and reliable Hb measurements with a smaller sample volume, improved turnaround time, and long-term cost saving.Keywords: haemoglobin, HemoCue®, point-of-care testing, anaemia screenin

The profile of orthopaedic sports medicine publishing in South Africa

Background: The South African Journal of Sports Medicine (SAJSM) and the South African Orthopaedic Journal (SAOJ) are two open access, peer-reviewed journals which provide ongoing education to the sports medicine community. Objectives: The purpose of this review was to appraise articles with a sports orthopaedic focus published in SAJSM and SAOJ. A secondary aim was to evaluate trends regarding the focus of the articles, levels of evidence, authors’ affiliations, and country of origin.  Methods: An electronic search of the SAJSM from 1982 to 2021 and SAOJ from 2008 to 2021 was conducted to identify relevant articles. The eligibility of the articles was determined according to the following inclusion criteria: SAJSM articles with reference to musculoskeletal anatomy and/or an injury in any sport, and SAOJ articles focusing specifically on sports, sports teams and low-velocity traumatic injuries in sports people.  Results: This study included specific sports orthopaedic articles in SAJSM (n=161) and SAOJ (n=41). The articles originated from 67 institutions in 19 countries. In SAJSM, the majority of articles were published by local authors (n=44, 61%). There was a non-significant difference in the proportion of articles from local and international institutions in SAOJ. In SAJSM, the sports covered most frequently included rugby, cricket, running and soccer, whereas in SAOJ most articles referred to low-velocity injuries. With regard to trend analysis, a significant decline in articles with Level V evidence published by SAJSM was observed (p<0.001). Similarly, articles with Level V evidence published by SAOJ showed a decline, although it was non-significant. Conclusion: The focus of SAJSM in particular is relevant to sports played, injury patterns and the healthcare resources for sports people in South Africa. The level of evidence published by SAJSM has improved significantly over time.

A case of a drug reaction to sulfasalazine in a patient infected with HIV

Introduction: The diagnosis of drug reaction with eosinophilia and systemic symptoms (DRESS) in human immunodeficiency virus (HIV) patients on multiple drugs with concomitant disorders presents a diagnostic challenge.Patient presentation: We describe a case of a drug reaction to sulfasalazine in a 46 year old HIV-infected female with concurrent rheumatoid arthritis which presented atypically with a marked peripheral blood plasmacytosis mimicking a lymphoproliferative neoplasm.Management and outcome: A diagnosis of DRESS was made in conjunction with the laboratory and clinical presenting findings. Sulfasalazine was immediately discontinued. The mucocutaneous rash and systemic symptoms (which included fever, lymphadenopathy and multi-organ dysfunction) resolved with supportive treatment. This included topical and systemic corticosteroids.Conclusion: In conclusion, it is important to consider drug reactions when evaluating patients infected with HIV

The clinical significance of current laboratory and other prognostic indicators in the management of South African children with Precursor B cell acute lymphoblastic leukaemia

M.Med.(Haematology), Faculty of Health Sciences, University of the Witwatersrand, 2008This study aimed to identify the relevance of these prognostic features in the modern treatment era in South African children. A retrospective analysis of the presentation clinical and laboratory features and treatment outcomes of all children treated for Precursor B cell ALL at the Johannesburg Hospital was performed. Between January 1997 and May 2007, 100 children were reviewed. Clinical features (age, race and gender) emerged as significant prognostic variables. Laboratory features (white cell count and genetic features) lacked significance. Early morphologic response on day 15 identified a subgroup associated with a favourable outcome. However the presence of > 5% blasts was not significantly predictive of relapse or death at this time point. Minimal residual disease (MRD) detection by modified immunoglobulin gene rearrangement and flow cytometry techniques did not improve the predictive value of the morphological assessment. In a low resource setting, the challenge is to design cost effective MRD detection methods to improve the identification of patients at risk for relapse

Validation of the CoaguChek XS international normalised ratio point-of-care analyser in patients at Charlotte Maxeke Johannesburg Academic Hospital, South Africa

Background. Measurement of the international normalised ratio (INR) is essential in the management of patients on long-term warfarin therapy. The CoaguChek XS portable coagulometer is a point-of-care test for INR measurement. It offers the advantage of improved patient accessibility, particularly in peripheral clinics.Objectives. To evaluate the clinical utility of the CoaguChek XS for monitoring of patients on standard warfarin therapy (INR 2 - 3) as well as those with mechanical heart valve replacements (INR 2.5 - 3.5).Methods. We compared the performance of the CoaguChek XS device with that of the STAGO laboratory analyser with regard to accuracy and precision in 304 patients referred for routine testing.Results. The mean INR value of the CoaguChek XS of 2.75 (standard deviation (SD) 1.18) was comparable to that of the STAGO (2.65 (SD 1.04)). The Bland Altman difference plot revealed good agreement. Bias between the two methods was small, and the imprecision was within acceptable limits. Within the target range (2.0 - 3.5), 93.9% of the CoaguChek XS INR readings were within 0.5 units of the standard laboratory method result. There was, however, an increase in the variability of the differences between the two test methods when the INR was >3.6.Conclusion. The CoaguChek XS point-of-care device can be used to provide accurate and precise INR measurements over a wide range for monitoring of valvular and non-valvular patients on long-term warfarin therapy

Thrombo-embolic and bleeding complications in patients with mechanical valve replacements - a prospective observational study

Background and objectives. Long-term anticoagulation therapy is essential to prevent thrombo-embolic events in patients with mechanical valve replacements. In order to offer indigent patients mechanical heart valve replacement surgery, dedicated anticoagulation clinics are necessary for follow-up. This study assessed the safety and efficacy of lifelong oral anticoagulation therapy in Johannesburg General Hospital mechanical heart valve replacement recipients. The incidence of bleeding and thrombo-embolic complications was documented in three groups of patients with mechanical valve replacements. The groups included patients with aortic valve replacements (AVRs), mitral valve replacements (MVRs) and double (aortic and mitral) valve replacements (DVRs). Materials and methods. A prospective observational study was conducted over a 4-month period. Data on 306 patients attending the Johannesburg General Hospital anticoagulation clinic between 2000 and 2005 were analysed. Of the total patients selected, 205 were assigned to the mechanical valve replacement group (which included 63 patients with AVRs, 93 with MVRs and 49 with DVRs); a control group of 101 nonmechanical valve replacement patients were also included. At each visit the level of anticoagulation was assessed from the international normalised ratio (INR) values, and the presence of bleeding and / or thrombo-embolic complications was documented. Results. There were a total of 51 bleeding and thrombo-embolic complications in the study population. Patients with DVRs had a higher proportion of combined complications (30.61%) than patients with single valve replacements (14.29% in the AVR group and 18.05% in the MVR group) and patients in the control group (12.87%). There were 38 bleeding complications, 30 minor and 8 major. Twelve thrombo-embolic events were documented. Individually, there was no significant difference in thrombo-embolic and bleeding complications between the subgroups. Eighty-two per cent of patients in the mechanical valve replacement group were within the therapeutic range for anticoagulant control (INR 2.5 - 3.5) v. 54% in the control group (INR 2.0 - 3.0). Anticoagulant control was of a high quality and was not a contributing factor to the incidence of bleeding and / or thrombo-embolic complications. Conclusion. The finding of a low incidence of bleeding and thrombo-embolic complications in patients with mechanical valve replacements supports the continued placement of mechanical valves in our setting and use of oral anticoagulation therapy at an INR of 2.5 - 3.5. However the increased risk of both bleeding and thrombo-embolic complications in the DVR group is cause for great concern and warrants further investigation. South African Medical Journal Vol. 96(8) 2006: 710-71

Thrombotic disorders (part 1)

Thromboembolic conditions are the leading cause of mortality, estimated to account for 1 in 4 deaths worldwide in 2010. Over time, the incidence and mortality rates of these conditions have improved in developed countries, but are increasing in developing countries. The haemostatic system comprises 6 main components, i.e. (i) platelets; (ii) vascular endothelium; (iii) coagulation proteins; (iv) natural anticoagulants; (v) the fibrinolytic system; and (vi) natural antifibrinolytic factors. A delicate balance exists between procoagulant and anticoagulant factors within the vascular system. Numerous acquired or inherited conditions may tip the balance either way, i.e. towards a prothrombotic or prohaemorrhagic state. In this issue of CME, the first of a 2-part series on thrombophilic disorders, the subject of discussion is on inherited varieties that the general practitioner is likely to encounter. This review is primarily based on venous thrombosis

Delayed hypersensitivity to low molecular weight heparin (LMWH) in pregnancy

Heparin is currently the anticoagulant of choice for the prevention and treatment of thrombo-embolic disease in pregnancy because it does not cross the placenta [1]. The use of low molecular weight heparin (LMWH) is preferred to unfractionated heparin (UFH) as it is associated with a lower risk of bleeding, osteoporosis, heparin induced thrombocytopenia (HIT) and hypersensitivity reactions [2, 3, 4, 5]. Fondaparinux can be considered as a valuable alternative to LMWH during pregnancy in those patients with heparin induced skin reactions and/or HIT