Behavior of red cell distribution width (RDW) in a population of anemic and non-anemic dogs from an ambulatory care unit.

Abstract

ResumoO objetivo deste estudo foi avaliar o comportamento do índice de anisocitose na interpretação do hemograma de cães anêmicos e não anêmicos. Atualmente, contadores hematológicos automatizados veterinários fornecem alguns índices que não são calculados quando o hemograma é confeccionado manualmente. A saber: RDW-CV (Amplitude de distribuição de hemácias como coeficiente de variação) e RDW-SD (Amplitude de distribuição de hemácias como desvio-padrão). Tais índices levaram a uma nova abordagem do paciente com anemia permitindo que a anisocitose fosse mensurada de uma forma quantitativa. Foram avaliados 454 hemogramas processados no período de setembro de 2009 a março de 2011. Foram calculados média e desvio padrão e uma análise de variância foi realizada. Os cães anêmicos (125/454) apresentaram altos valores de RDW enquanto que, em animais não anêmicos, esse índice permaneceu dentro dos valores de normalidade previamente estabelecidos. O índice também estava alto em animais com anisocitose observada à microscopia. Houve uma diferença significante entre os índices dos animais que apresentaram Volume Globular Médio (VGM) elevado e normal. Concluiu-se que os índices RDW-CV e RDW-SD foram sensíveis a pequenas variações no tamanho das hemácias e na heterogeneidade, sendo mais precisos que a observação microscópica para se detectar anisocitose e mais sensível que VGM para variação eritrocitária.Palavras-chave: anemia, anisocitose, contador hematológico automatizado, hematologia. AbstractThe aim of this study was to evaluate the behavior of the red cell distribution width (RDW) in the interpretation of the Complete Blood Count (CBC) from anemic and non-anemic dogs. Currently, automated veterinary blood cell analyzers provide hematologic indices not calculated in manually performed CBC, such as Red Blood Cell Distribution Width measured by Variation Coefficients (RDW-CV) and Red Blood Cell Distribution Width measured by Standard Deviation (RDW-SD), which has led to new of September 2009 to March 2011. Mean and standard deviation were calculated and variance analysis was performed. Anemic dogs (125/454) presented higher values for RDW indices. In non-anemic animals, these indices were in accordance with the normal values previously established. Both indices were higher in dogs with microscopic observation of anisocytosis. There was a significant difference among índices of the animals which showed normal and increased Mean Corpuscular Volume (MCV). We concluded that RDW-CV and RDW-SD indices were sensitive to small variations on erythrocyte size and heterogeneity, being more accurate than microscopic observations to detect anisocytosis and more sensitive than MCV to erythrocyte variation.

Evaluation of Red Cell Distribution Width (RDW) in Anemic Goats

“…The measurement of red blood cell distribution width (RDW) could provide a newer approach to the anemia (Souza et al, 2012). Souza et al (2017) reported RDW as a sensitive tool to assess erythrocyte sizes and variations and found more accurate than microscopic observations in detecting anisocytosis. It was also found more sensitive than MCV in assessing erythrocyte variations.…”

“…Extensive studies indicated Red Blood Cell Distribution width was used as a perdiction factor in various disease conditions in human medicine especially in cardiovascular disease (Patel et al, 2013), iron deficiency anemia (Piriyakhuntorn et al, 2018) and pulmonary hypertension (Yang et al, 2019). Further, few studies in Veterinary Medicine were also reported with special reference to canines anemias (Souza et al, 2017), pulmonary hypertension (Swann et al, 2014 and other illnesses (Martinez et al, 2019). The red blood cell distribution width (RDW) means measurement of degree of anisocytosis in the erythrocyte population and expressed as the coefficient of variation of the erythrocyte size distribution (Pastor et al, 1997;Hammarsten et al, 2010).…”

Comparison of visual assessments of anisocytosis in canine blood smears and analyzer-calculated red blood cell distribution width

“…Variability in erythrocyte size, anisocytosis, is useful for the describing, classifying, or prognosing of pathophysiological phenomena in dogs ( 1 – 4 ), such as anemia ( 5 – 9 ), microcytosis ( 10 , 11 ), quatrefoil red blood cells ( 12 ), cardiopulmonary diseases ( 13 – 18 ), pancreatitis ( 19 ), inflammatory bowel disease ( 20 ), or diabetes mellitus ( 21 ), and of physiological phenomena such as sex and aging ( 22 , 23 ).…”

“…Evaluating a blood smear by conventional microscopy requires experience ( 26 ) and is prone to subjective assessment, which may lead to variability within and between observers. Furthermore, different grading schemes exist, some with very simple categorizations such as “absent or present” ( 9 , 22 ). Others have applied subjective grading on a scale from +1 to +4, with +1 being the smallest amount ( 27 ), or grading +1 to +4 based on the number of variable-sized erythrocytes in a monolayer at 1,000x microscopic field ( 28 ) or high-power field (HPF) ( 21 ).…”

“…One study by Kumiega et al ( 16 ) found that RDW results were within the reference range for dogs with degenerative mitral valvular disease while manual microscopic analysis of the blood smears revealed the presence of anisocytosis, although no direct correlation was reported. de Souza et al ( 9 ) communicated that, in cases where anisocytosis was observed in blood smears in anemic dogs, these dogs also had higher RDW values and concluded that RDW values were more accurate than microscopic observations to detect anisocytosis.…”