Events on 27 September 2023

Cell blocks from Diagnostic Cytopathology (DC) samples have always had value in the diagnostic process as a complement to the traditional cytology stains – Papanicolaou and Romanowsky. It has become more important to provide material for Immunocytochemistry to refine malignant diagnosis, and more recently, the use of molecular testing to aid in the choice of tailored chemotherapy regimens. If this information can be obtained from DC samples, which are less invasive than biopsy samples, the patient will benefit.

External Quality Assurance of cell block preparations has up to now been covered by the Tissue Diagnostic scheme. However, this is not entirely appropriate as cytopathology departments use a variety of cell block preparation methods and fixatives. The increase in number of cell block Haematoxylin and Eosin slides submitted to our evaluation service and the queries we receive regarding advice on best preparation methods suggested there was a need for a separate scheme for evaluation of cell blocks. A circulated survey indicated that there is a need for such a scheme. In response to this we performed 2 pilot studies which were well supported and successful, leading to the launch of the live scheme in April 2023.

This presentation covers the development of the scheme and the results of the 2 pilots. As an ongoing process the scheme will be able to garner information about ‘best methods’ and this can be passed on to laboratories experiencing problems and improve standards. UKNEQAS CPT is not just a ‘tick box’ service for UKAS, it is also an advisory service which aims to improve diagnostic practices.

Whats new in Diagnostic Cytology (Reporting systems; biomarker testing)

vWF Guideline Update

Thrombophilia is defined as hereditary and/or acquired conditions associated with an increased predisposition to thrombosis. The previous British Society for Haematology guideline on thrombophilia testing (2012) focused only heritable thrombophilia testing. The updated guideline published in 2022 (1) has a widened scope to include both heritable and acquired thrombophilia especially antiphospholipid antibodies, paroxysmal nocturnal haemoglobinuria, myeloproliferative neoplasm (MPN) and the presence of a JAK2 mutation in the absence of an MPN phenotype. Disorders such as cancer, inflammatory conditions and obesity are associated with thrombosis through multiple mechanisms, but these are not included in the guideline which focuses only the factors identified from laboratory testing.

The key principle in the guideline is that when clinical utility of testing is not clear, thrombophilia testing is not mandatory, and testing should be done only if the result will alter the management of the patient. These guidelines emphasise the importance of identifying antiphospholipid syndrome and JAK2 +/- MPN phenotype because they have a significant impact on management. The guidelines confirm the limited utility of testing for hereditary thrombophilia testing in venous thromboembolism, arterial thrombosis and recurrent pregnancy loss.

1. Arachchillage, DJ, Mackillop, L, Chandratheva, A, Motawani, J, MacCallum, P, Laffan, M. Thrombophilia testing: A British Society for Haematology guideline. Br J Haematol. 2022; 198: 443– 458. https://doi.org/10.1111/bjh.18239

The effects of long COVID on coagulopathy

Effects of direct thrombin inhibitors [dabigatran/argatroban/bivalirudin] on tests of haemostasis

Meet your Haematology Portfolio examiners

A case study into iron deficiency polycythaemia diagnosis, looking at the pathology and how this relates to the results we see and investigations to confirm diagnosis.

Transient Abnormal Myelopoiesis

Coagulopathy has been shown to play an important role in COVID 19 infection. Reported abnormal coagulation laboratory values in severe COVID-19 are most notably a 3-to-4-fold increase in D-Dimer (Yao et al., 2020).

Several studies showed that elevated D-dimer in COVID-19 patients is associated with higher mortality. A retrospective cohort study carried out by Zhou, et al. (2020) also associated D-Dimer > 1000ng/ml with higher odds of in-patient death.

At the onset of the COVID 19 pandemic, there was no consensus as to how D-Dimer levels should be used for the management of COVID-19 patients. In April 2020, PAHT decided to use a D-Dimer cut-off of 1000 ng/ml to determine anticoagulation dosage. The source of reference used by PAHT in their decision making employed a D-Dimer assay with a cut off value of 500 ng/ml for the exclusion of venous thromboembolism (VTE). This raised an issue as the source of reference used by PAHT at the time employed a D Dimer assay with a cut-off value of 230 ng/ml for the exclusion of VTE. This meant the trust was unable to implement the new COVID 19 care bundle at the time. The haematology laboratory wanting to do whatever possible to assist patient care agreed to change the current D-Dimer methodology immediately to support the trust COVID 19 care bundle.

The verification and implementation of the new D-Dimer assay with cut of 500 ng/ml for the exclusion of VTE was completed within four weeks. A risk assessment and a change control were put in place to ensure users were made aware of the change in cut-off limit.

This verification and implementation of the new assay was possible through the hard and collaborative work of the haematology technical team with shared vision, motivation coupled with team engagement and strong leadership.