Elise Schapkaitz

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.

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

OBJECTIVE 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 <6 and >20 g/dl, platelet count <41 and >1 000 ×10(9)/l, white cell count <2 and >46 ×10(9)/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 patients 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 laboratorys 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 policies.

Maintenance of Warfarin Therapy at an Anticoagulation Clinic

Patients should be referred to an anticoagulation clinic only after being adequately anticoagulated. The referring doctor should perform any adjustments to the initial dosage of warfarin. The general care of the patient remains the responsibility of the referring doctor. Any bleeding and thrombo-embolic events must be reported and managed by the referring doctor and / or referred to an appropriate specialist.

Paediatric anticoagulation guidelines.

Prepared on behalf of the South African Society of Thombosis and Haemostasis. Background. Recent progress has been made in the understanding of venous thrombo-embolism (VTE) in children and neonates; however, indications for laboratory investigations and therapeutic interventions are not well defined. Method. The Southern African Society of Thrombosis and Haemostasis reviewed available literature and comprehensive evidence-based guidelines for paediatric antithrombotic therapy. A draft document was produced and revised by consensus agreement. The guidelines were adjudicated by independent international experts to avoid local bias. Results and conclusion. We present concise, practical guidelines for the clinical management and laboratory investigation of VTE in children and neonates. Recommendations reflect current best practice which will hopefully lead to improved anticoagulation practice in this age group.

Customised Critical Limits Help to Achieve Efficient Use of the Laboratory’s Resources

Background: Customisation of critical value policies in laboratories with increasing workloads helps to achieve efficient use of laboratory’s resources. Methods: The critical value policy at an academic hospital was customised with the introduction of a new middleware (Sysmex Corporation, Kobe, Japan). The number of notifications over a one-month period was reviewed in order to determine the impact of customisation on laboratory resources and patient safety. Results: 1891 haematology critical values were identified. 1195 (63%) results did not require notification according to the customised policy. Of these, 1034 (55%) had a previous critical result, 89 (5%) were not phoned as per customer request and in 72 (4%) the critical result was already viewed by the clinician. Conclusion: Customisation resulted in a marked reduction in the critical results requiring notification. Laboratory information system middleware can be developed to consider factors such as, a change in the current result from previous results, patient location and requesting doctor to customise notification.

Stability of New Erythrocyte and Reticulocyte Parameters in Testing for Anemia on the Sysmex XN 9000

Background New erythrocyte and reticulocyte parameters provide improved classification of anemia and monitoring of erythropoeitic activity. Parameters available on the Sysmex XN analyzers include the percentage of microcytic red blood cells (%Micro-R), percentage of macrocytic red blood cells (%Macro-R), percentage of hypochromic red blood cells (%Hypo-He), percentage of hyperchromic red blood cells (%Hyper-He), reticulocyte hemoglobin content (Ret-He), and immature reticulocyte fraction (IRF). However, use of these parameters is limited by specimen stability. Methods To verify the stability of the new erythrocyte and reticulocyte parameters during prolonged storage, 20 blood specimens were analyzed on the Sysmex XN-9000 hematology analyzer. The specimens included healthy patients (60%) and patients with anemia (40%). The specimens were stored at room temperature (RT) and at 4° to 8°C. Analysis was performed after 12, 24, 48, and 72 hours of storage. Results Reticulocyte parameters IRF and Ret-He were precise and stable for at least 72 hours after collection when stored at RT and 4° to 8°C. The volume-dependent parameters, %Macro-R and %Micro-R, were stable for less than 12 hours after collection at RT (mean [SD%], 6.55 [3.19%] and -20.70 [10.37%], respectively). Storage at 4° to 8°C showed a reduction in osmotic swelling. However, %Macro-R and %Micro-R were stable for less than 12 hours after collection (mean [SD%], 4.89 [2.02%] and -17.17 [8.38%], respectively). Similarly, %Hypo-He showed a mean (SD%) increase of 0.73 (4.05%) and %Hyper-He showed a decrease of -0.70 (9.72%) at less than 12 hours after storage at 4° to 8°C. Conclusion New reticulocyte parameters stored at RT and 4° to 8°C are suitable for testing on the Sysmex XN analyzer.

The Diagnostic Challenge of Acquired Thrombotic Thrombocytopenic Purpura in Children: Case Report and Review of the Literature

Acquired thrombotic thrombocytopenic purpura (TTP) is a rare disease in children. Despite advances in diagnosis and treatment, acquired TTP remains a challenging disease due to the lack of a simple diagnostic test and the variable response to plasma exchange. Herein, we describe a case of a 5-year-old of black ethnicity boy who presented with a sudden onset of fatigue and body aches. Laboratory investigations revealed a thrombotic microangiopathic manifestation. TTP was diagnosed, and plasma exchange and corticosteroids were initiated, with an excellent response. Subsequently, reduced disintegrin and metalloprotease with thrombospodin-2-like repeats (ADAMTS-13) activity and human immunodeficiency virus (HIV) were confirmed. Antiretroviral treatment was started as long-term management. At last follow-up, he continues in stable remission.

Differences in erythrocyte sedimentation rates using a modified Westergren method and an alternate method

Worldwide laboratories have adopted the use of modified or alternate methods for measurement of the erythrocyte sedimentation rate (ESR). The iSED from Alcor Scientific is a novel, alternate ESR method based on photometric aggregometry which offers improved operator safety and reduced analysis time. This study evaluated the diagnostic utility of the iSED in a South African patient population with a range of inflammatory disorders.

Performance evaluation of the white cell precursor channel on the Sysmex XN hematology analyzer in HIV specimens

Automated hematology analyzers generate white blood cell (WBC) suspect flags to indicate smears requiring manual review. In a human immunodeficiency virus (HIV) patient population with a high frequency of abnormal specimens, the usefulness of these flags depends on their sensitivity and specificity. The white cell precursor (WPC) channel on the Sysmex XN‐9000 analyzer (Sysmex Corporation, Kobe, Japan) has recently been introduced in order to distinguish immature cells such as blasts and abnormal lymphocytes.

Conservative Management of Overanticoagulation in Patients With Low–Moderate Risk for Bleeding Complications

Despite long-standing experience with warfarin, anticoagulation clinic services are often confronted with the challenging clinical situation of patients with overanticoagulation. This requires repeat international normalized ratio (INR) monitoring and in some cases administration of vitamin K to minimize the risk of bleeding. A study was performed to determine the safety and efficacy of outpatient management in order to provide guidance on the management of patients with prolonged INRs. Patients on stable warfarin therapy for more than 1 month attending a dedicated academic hospital anticoagulation clinic who had an INR ≥5 were identified over a 1-year period. Follow-up INR results and outcomes were recorded for 30 days. One hundred and ninety-five episodes of overanticoagulation in 148 patients were identified. Patients were classified as low risk (n = 85, 57.4%) and moderate risk of bleeding (n = 63, 42.6%). The mean index INR was 7.22 (1.88). Management with low-dose oral vitamin K (n = 32, 16.4%) did not significantly result in a more rapid correction of the INR when compared to conservative management (n = 163, 83.6%; P = .103). Follow-up INR testing was performed at a mean of 11.1 (8.9) days from the index measurement. A mean of 1.6 (0.9) follow-up INR tests were performed per episode. During the 30-day follow-up, there was 1 (0.5%) episode of major bleeding and 1 (0.5%) death. The management of asymptomatic outpatients with overanticoagulation is associated with a low risk of major bleeding within 30 days. Conservative management of overanticoagulation is as effective as utilizing low-dose oral vitamin K.