Comparison of Detection Rate of Acid-fast Bacilli in Sputum Samples with Different Collection Time and Property

Objective To compare the detection rate of acid-fast bacilli in sputum samples from different collection time and sputum property,and to explore the relation between the detection rate of acid-fast bacilli and sputum samples from different collection time and property.Methods The smear acid-fast bacilli and Ziehl-Neelsen staining were used to analyze the difference of smear-positive rate in sputum samples from different collection time and sputum property.Results There were statistically significant differences in the smear results of 3,249 caseous,blood or mucus sputum samples collected from the instant,night or early morning.The positive detection rates from early morning and caseous samples were 30.75% and 70.03% respectively.There were statistically significant differences in the distribution of the positive samples and the amount of acid-fast bacilli in sputum samples from different collection time and property.There were statistically significant differences in the positive detection rates between the smear samples by visual selection and selection at random.Conclusions The detection rate of acid-fast bacilli in sputum samples is notably influenced by different collection time and sample quality.The positive detection rates of early morning sample and caseous sputum sample are the highest.Visual selection of caseous or purulent sputum samples can significantly increase the positive detection rate.