AimTo compare the frequently used CD138 immunohistochemistry-based method of plasma cell quantitation, to a proposed new method, using interobserver and intraobserver concordance parameters.MethodsArchival CD138 immunohistochemically stained slides made from paraffin-embedded bone marrow biopsies of 33 patients with a confirmed diagnosis of multiple myeloma were used. Light microscopic examination was performed using low magnification lenses (10×) for both the overview estimation method (method A) and the new method (method B), and high magnification lenses (50×), for method B only. For method B, reviewers selected three areas with low, intermediate and high plasma cell densities using 10× lenses. Using a well-defined technique, the 50× lens was then used to count plasma cells as a percentage of all nucleated cells. After blinded relabelling of all the slides, the nine reviewers repeated the plasma cell quantitation using both methods. The plasma cell counts were obtained, and the review times were recorded.ResultsOverall intraobserver concordance was comparable for method A (concordance correlation coefficient (CCC)=0.840) and method B (CCC=0.733). Interobserver concordance for method A (intraclass correlation coefficient (ICC)=0.793 and 0.713) and method B (ICC=0.657 and 0.658) indicated high similarity between reviewers. Method A showed poor interobserver concordance (ICC=0.105) at low plasma cell densities.ConclusionsThe new method is comparable to the frequently used overview estimation method in terms of intraobserver and interobserver concordance, and cost. The new method has superior interobserver concordance at low plasma cell densities. The new method appears more amenable to digital scanning and analysis.

Background: Coronavirus disease 2019 (COVID-19) is associated with hematological abnormalities of variable severity. The full blood count (FBC) and leukocyte differential count (DIFF) could facilitate the prediction of disease severity and outcome in COVID-19. This study aimed to assess the hematological parameters in early severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and their correlation with disease outcome. Methods: A retrospective cross-sectional descriptive study was performed. Adults with a FBC and positive SARS-CoV-2 polymerase chain reaction results between March 1, and June 31, 2020 were reviewed. Basic hematological parameters (FBC, DIFF) and human immunodeficiency virus (HIV) status were recorded. Outcome measures were admission to a general ward or intensive care unit (ICU), recovery or death.Results: Six hundred and eighty-five cases median age 51 years, were analyzed.Forty-four percent were males and fourteen percent were HIV-positive with no association between death and/or ICU admission (p = 0.522 and p = 0.830, respectively). Leucocytosis was predictive of ICU admission (odds ratio [OR]: 2.4, confidence interval [CI]: 1.77-3.8186) and neutrophilia, of both mortality (OR: 1.5, CI: 1.0440-2.0899) and ICU admission (OR: 4, CI: 2.5933-6.475). Median lymphocyte count was decreased and D-dimer raised, showing no significant association with outcome. Raised neutrophil-to-lymphocyte-ratio (NLR) was associated with increased odds of mortality (OR: 2.5, CI: 1.3556-3.2503) and ICU admission (OR: 4.8, CI: 2.4307-9.5430) as was monocyte-to-lymphocyte-ratio (MLR) (OR: 2, CI: 1.3132-2.9064) and (OR: 2.3, CI: 1.0608-1.9935), respectively. Hospital admission and older age were significantly associated with mortality (p = 0.0008 and p < 0.0001), respectively.