Differential cell count of induced sputum and natural sputum smear

    WEI Weiª²Li, L¦a Hanª²Jing, YANG Zhongª²Min, HONG Guangª²Chao, LIU Ruiª²Lin, QIU Zhongª²Min

    Department of Respiratory Medicine, Affiliated Tongji Hospital, Tongji University, Shanghai 200065, China

    ¡¾Abstract¡¿ AIM: To investigate the cell viability between induced sputum and natural sputum smear. METHODS: A tenª²month randomized, doubleª²blinded and controlled trial was conducted in our Department of Respiratory Medicine. Between July 1, 2003 and April 5, 2004, the sputum smears with or without 14 mL of 4% saline inhaled via an ultrasonic nebulizer were harvested randomly at 4 to 5 hours interval and total 43 natural sputum smears and 56 induced sputum smears from 59 patients with respiratory diseases such as asthma, cough variant asthma and chronic obstructive pulmonary diseases were obtained. We divided the 43 induced sputum and the corresponding 43 natural sputum of the same patients into two groups. After the smears of both groups were stained with Giemsa solution, the number and percentage of monocytes, lymphocytes, neutrophils, eosinophila and granulocytes under per high power field were compared between the induced and natural sputum smears of the same patient. RESULTS: Induced sputum and natural sputum were obtained by 95% and 73% respectively (¦Ö2=10.60, P<0.01). The count of monocytes, lymphocytes, neutrophils and eosinophila of induced sputum and natural one was respectively 45.50¡À25.41 and 38.50¡À21.50, 31.25¡À8.24 and 27.25¡À7.19, 40.00¡À21.66 and 32.75¡À17.73, 3.50¡À1.53 and 2.50¡À1.09 under per high power field (P<0.05) and their percentage was respectively (37.8¡À21.1)% and (38.1¡À21.3)%, (26.0¡À6.8)% and (27.0¡À7.1)%, (33.3¡À18.0)% and (32.4¡À17.6)%, (2.9¡À1.3)% and (2.5¡À1.1)%, (P>0.05). CONCLUSION: Sputum induced by four percent saline inhaled via an ultrasonic nebulizer is more effective than natural sputum for the induced sputum. Cell count is higher but the percentage of monocytes, lymphocytes, neutrophils and eosinophila of induced sputum is the same as that of natural sputum. ......