SPUTUM EOSINOPHIL COUNT CORRELATES WITH BLOOD EOSINIPHIL COUNT AND CAN DIFFERENTIATE ASTHMA AND COPD,DR.D.K.JHA.M.D.,
Sometimes ,it becomes difficult to differentiate asthma,COPD and asthma-COPD overlap
It is easy to take sputum sample in adult, but in children it is difficult
So,any sample can be used depending upon the age of patient,if both correlates well
Researchers from Japan retrospectively,evaluated 195 patients with Asthma(n95),COPD(n61) and asthma COPD overlap(n39) between 2015 to 2017
Sputum sample was centrifuged at 500g for 5 minutes,then transferred to a glass slide.It was then crushed with a rotatory motion with another glass slide.Cell counts were done after proper staining.
To assess whether the sputum eosinophil counts-/>3% correlates with blood eosinophil count,researchers constructed ROC(Receivers operative curve)
Patients with Asthma and asthma COPD overlap had significantly higher eosinophil count and lower neutrophil counts during stable period as compared to patients with COPD . But it was not so during exacerbations.
MEAN eosinophil and neutrophil counts: asthma, 17.4% and 78.8%, respectively; COPD, 1.8% and 95.6%, respectively; and asthma-COPD overlap, 11.8% and 84.2%, respectively).It was during stable period
But,during the periods of exacerbation, following was the results
MEAN eosinophil and neutrophil counts: asthma, 15.0% and 83.3%, respectively; COPD, 4.8% and 86.4%, respectively; and asthma-COPD overlap 17.7% and 79.9% respectively.
There was significant correlations between blood and sputum eosinophil percentage among all categories of patients both during stable and during the period of exacerbations
It was clear from the analysis of ROC curve, that the blood eosinophil can predict sputum eosinophil count3% during stable period as well as during the period of exacerbations.Following is the results.
During stable period (AUC, 0.75 [95% CI, 0.66-0.84]; cutoff, 235 µL; sensitivity, 75.4% and specificity, 71.3%) and during the exacerbation period (AUC, 0.80 [95% CI, 0.66-0.94]; cutoff, 351 µL; sensitivity, 61.1% and specificity, 97.1%).
So we can take either sample according to feasibility and during the stable period ,we can diffferentiate between asthma,COPD and asthma COPD overlap
REFERENCES:
Tamura K, Shirai T, Hirai K, et al. Differentiation of asthma, COPD, and asthma-COPD overlap via a simplified sputum cell count method. Presented at: CHEST Annual Meeting 2019; October 19-23, 2019; New Orleans, LA. Abstract 464.