Peripheral Blood Morphology and Hemogram in COVID-19 Patients Correlates with Disease Severity
Authors: Mishra Priyanka , Agarwal Samir , Patni Preeti , Pathak Sukant , Kaur Mandeep , Rehman Nidhin 
Published: August 2024

Context:
Coronavirus Disease 2019 (COVID-19) has profound hematopoietic manifestations reflected in complete blood count (CBC) parameters and peripheral blood morphology.

Aims:
We aimed to evaluate CBC and peripheral blood morphology in COVID-19 patients and correlated them with severity, progression, and mortality.

Settings and Design:
Prospective observational study.

Methods and Materials:
Baseline and sequential blood samples were collected in 197 hospitalized COVID-19 patients, and CBC and morphology were assessed and compared with severity, progression, and survival.

Statistical Analysis Used:
Independent samples t-test for parametric continuous and Chi-Square and Fisher Exact for categorical variables.

Results:
Of the 197 patients, 84 (42.6%) were non-severe and 113 (57.4%) severe. The severe group displayed higher mean Total leukocyte count (TLC) (mean 11,772/μL SD 5445 vs. mean 7872/μL SD 3789, P < 0.0001), neutrophils (mean 81.2% SD 17.01 vs. mean 59.8% SD 14.55, P < 0.0001), and Red Cell Distribution Width-Standard Deviation (RDW-SD) (mean 30.04 SD 17.1 vs. mean 16.95 SD 6.63, P < 0.0001) with lymphopenia (mean 12.86% SD 15.41 vs. mean 30.64% SD 13.23, P < 0.0001) and monocytopenia (mean 4.62% SD 3.56 vs. mean 7.23% SD 3.06, P < 0.0001). The severe group had significantly more pseudo Pelger-Huet (62.8% (71/113) vs. 22.9% (14/61), P < 0.0001), abnormal nuclear projections (27.4% (31/113) vs. 3.3% (2/61), P < 0.0001), elongated nucleoplasm (17.7% (20/113) vs. 3.3% (2/61), P = 0.0073), shift to left (100% (113/113) vs. 21.3% (13/61), P < 0.0001), prominent granules (100% (113/113) vs. 85.2% (52/61), P < 0.0001), cytoplasmic vacuolations (100% (113/113) vs. 50.8% (31/61), P < 0.0001), ring (8.3% (3/113) vs. 4.9% (3/61), P = 0.0117), fetoid (15.04% (17/113) vs. 1.6% (1/61), P = 0.039), and nucleolated forms (53.9% (61/113) vs. 21.3% (13/61), P < 0.0001) with red cell agglutination (8.8% (10/113) vs. 0% (0/61), P = 0.0154) than non-severe patients. The non-severe group showed lympho-plasmacytoid (98.4% (60/61) vs. 37.2% (42/113), P < 0.0001), monocytoid (96.7% (59/61) vs. 25.7% (29/113), P < 0.0001), apoptotic (100% (61/61) vs. 17.6% (20/113), P < 0.0001), and nucleolated lymphocytes (78.7% (48/61) vs. 5.3% (6/113), P < 0.0001) with prominent granules (80.3% (49/61) vs. 12.4% (14/113), P < 0.0001), cytoplasmic vacuolations (83.6% (51/61) vs. 30.1% (34/113), P < 0.0001), and plasma cells (45.9% (28/61) vs. 19.5% (22/113), P = 0.0004). The progressors (9/84) had baseline leukocytosis (TLC mean 15,889/cu mm SD 4163.96 vs. mean 6940.27/cu mm SD 2381.59, P < 0.0001) and lymphopenia (lymphocyte% mean 18.11% SD 10.75 vs. mean 32.1% SD 12.75, P = 0.0022) with elevated RDW-SD (P = 0.032) at 7th to 10th day of illness. The 14 non-survivors had significant thrombocytopenia (mean 63.35 × 103/μL SD 30.72 vs. mean 230.77 × 103/μL SD 98.77, P < 0.0001) with lymphocytes nadir at day 9 without recovery versus day 7 to 8 nadir before recovery in survivors.

Conclusions:
The peripheral blood morphological features are distinct in severe and non-severe COVID-19 patients and baseline leukocytosis, lymphopenia, and elevated RDW-SD at day 7 of illness are useful indicators of disease progression.