Antiphospholipid Antibody Testing: An Audit on Testing Practices in a Public Tertiary Care Center

BACKGROUND

Antiphospholipid antibodies (aPLs) are antibodies directed against cell membrane components and can be associated with clinical features or be asymptomatic. Testing and interpreting these antibodies is associated with many challenges and pitfalls in clinical practice.

OBJECTIVE

To review all antiphospholipid antibody testing and describe the testing practices, indications for testing and interpretation of results to infer local challenges with aPL testing and subsequently address ways to overcome those challenges.

METHODS

This is a retrospective analysis of all aPL testing done in a tertiary center between 2014 and 2018. Characteristics of study patients collected through chart review were described using the mean and standard deviation for continuous variables and proportion for categorical variables. Group differences were compared between patients with any aPL-positive result and those with no positive result using chi-square or Fisher's exact test as appropriate for categorical variables and a simple regression model for numerical variables.

RESULTS

Among 414 patients undergoing aPL testing, mainly adult females, 62 (14.9%) patients had at least one positive antibody, of those, 26 (42%) had repeat testing done. Testing was mostly done for obstetric indication (107, 25.8%), with 36 patients having one or two early pregnancy losses <10 weeks as their testing indication. A total of 27 (6.5%) patients were labeled with APS/possible APS based on chart review, but on review of the testing of those patients according to classification criteria, only nine patients satisfied the criteria for APS.

CONCLUSION

This study highlights the clinical challenges associated with aPL testing, including the controversies around indication for testing, the low rates of repeat testing to confirm persistence, and the common misinterpretation of results. Having an aPL testing profile, explicit reference ranges, results commentary, and close interaction between ordering physicians and laboratory staff might be starting points to overcome these challenges.

Predisposing Factors and Incidence of Venous Thromboembolism among Hospitalized Patients with Sickle Cell Disease

Though patients with sickle cell disease (SCD) are at risk of developing venous thromboembolism (VTE), clear estimates of its incidence and predisposing factors in hospitalized SCD patients are not available. Therefore, this issue was addressed to facilitate an early diagnosis and initiate appropriate prophylactic and treatment strategies. A retrospective observational study was conducted on patients with SCD who were admitted to an academic center in Saudi Arabia over a 10-year period. We identified 1054 admissions of 394 patients with SCD. Of the 3% of patients identified with VTE, 50% experienced pulmonary embolism (PE), 34.3% exhibited deep vein thrombosis (DVT), 6.3% exhibited cerebral vein thrombosis, and 9.4% showed other forms of VTE. In pregnant SCD patients, 6.4% developed a VTE event during their hospital admission. Of the risk factors, high white blood cell count, length of stay, and presence of any additional risk factor for VTE was associated significantly with higher risk of VTE. In our study, this risk seems to be much lower, which is likely attributed to the use of VTE prophylactic strategies implemented in our center. Nevertheless, further studies are needed to establish the ideal prophylactic strategy in patients with SCD.

Primary Central Nervous System Burkitt Lymphoma, Presenting with Long-Term Fluctuating Level of Consciousness: A Case Report and Literature Review on Challenges in Diagnosis and Management

Patient: Male, 65-year-old

Final Diagnosis: Primary CNS Burkitt lymphoma

Symptoms: Flactuating level of consciousness

Medication: —

Clinical Procedure: —

Specialty: Hematology

Low clinical utility of testing for anti-platelet factor 4 in asymptomatic individuals after ChAdOx1 nCoV-19 vaccine

INTRODUCTION

The development of anti-platelet factor 4 (PF4) antibodies is linked to a rare thrombotic complication described now as vaccine-induced immune thrombotic thrombocytopenia (VITT). This clinical syndrome with thrombosis and thrombocytopenia was reported after exposure to the Oxford-AstraZeneca COVID-19 vaccine, ChAdOx1 nCoV-19 vaccine (AZD1222), and Ad26.COV2.S vaccine (Janssen/Johnson & Johnson). In the absence of the clinical features, the incidence of positive anti-PF4 antibodies in asymptomatic individuals post-vaccination is unclear.

METHODS

The aim of this study was to evaluate the development of anti-PF4 antibodies in asymptomatic individuals 14-21 days after receiving the first dose of ChAdOx1 nCoV-19 vaccine (AZD1222) and BNT162b2 vaccine. Prospectively, we collected serum from individuals before and after ChAdOx1 nCoV-19 vaccine and BNT162b2 vaccine and measured anti-PF4 antibodies using the Asserachrom HPIA IgG ELISA (Stago, Asnieres, France).

RESULTS

We detected positive anti-PF4 antibodies in 5 of 94 asymptomatic individuals post-vaccine with a rate of 5.3% with low titers (OD 0.3-0.7). Four of 5 individuals who tested positive after the vaccine had also positive anti-PF4 antibodies before the vaccine, which indicates that a majority of the positive results are due to preexisting anti-PF4 antibodies. We did not find a relation between the development of anti-PF4 antibodies and the immune response to the vaccine, status of prior COVID-19 infection, and baseline characteristics of participants. None of the participants developed thrombosis nor thrombocytopenia.

CONCLUSION

Our results provide new evidence to guide the diagnostic algorithm of suspected cases of VITT. In the absence of thrombosis and thrombocytopenia, there is a low utility of testing for anti-PF4 antibodies.

Web-based expert system with quick response code for beta-thalassemia management

β-thalassemia is an inherited blood disorder in which the body cannot produce hemoglobin normally. Since patients with this condition receive blood transfusions regularly, iron builds up primarily in organs such as the heart, liver and endocrine glands. Accumulation of iron in the organs necessitates chelation therapy. These patients must visit the hospital frequently to assess and follow up on their health condition. Physician intervention is required after each regular assessment to adjust the treatment. Lifelong healthcare support using a web-based expert system with a quick response code is designed for β-thalassemia management in order to deliver benefits to patients, physicians, and other healthcare providers. The aim of this study is to implement a web-based expert system for β-thalassemia management in order to provide treatment recommendations and support the lifelong healthcare of patients. The system provides patient-related details, such as medical history, medicines, and appointments, in real-time. It has been also tested in real-life cases and shown to enhance β-thalassemia management.