Selvakumar N, Kumar Vanaja, Gopi P G, Sivagamasundari S, Narayanan P R
Bacteriology Department, Tuberculosis Research Centre, Indian Council of Medical Research, Chennai, India.
Indian J Med Res. 2008 Dec;128(6):765-8.
BACKGROUND & OBJECTIVES: Sputum acid-fast bacilli (AFB) microscopy services are not available in all health facilities. Alternative procedures are needed to transport sputum samples to the diagnostic centres for detection of AFB. The objective of the present study was to evaluate sputum smears made by pot-method with the direct smears made immediately after sputum collection by Ziehl-Neelsen (ZN) method.
Ninety three sputum samples from 49 pulmonary tuberculosis suspects were studied. Their direct smears (ZN smears) were stained by hot ZN method. The samples were then mixed with phenol ammonium sulphate basic fuchsin solution and stored at ambient conditions. The smears (pot smears), made on day 7, were then, decolourized and counter-stained for detection of AFB (pot method). The ZN and pot smears were read blind. After excluding 18 samples for various reasons, the results of pot and ZN smears of 63 samples from smear positive (2 of 3 direct smears were positive) and 12 from smear negative (3 of 3 direct smears were negative) patients were analysed. ZN method was the gold standard.
Pot and ZN smears were positive in 61 of 63 samples from smear-positive patients and negative in 11 of 12 smear-negative patients (kappa = 0.87). The sensitivity and specificity of pot method were 96.8 and 91.7 per cent respectively.
INTERPRETATION & CONCLUSION: Sputum samples can be stored for up to seven days in the sputum container with phenol ammonium sulphate basic fuchsin solution. However, a comprehensive study needs to be done confirm the accuracy of the pot method for storage and transportation of sputum to microscopy centres for detection of AFB.
并非所有医疗机构都能提供痰涂片抗酸杆菌（AFB）显微镜检查服务。需要采用其他方法将痰标本运送至诊断中心以检测AFB。本研究的目的是评估采用酚法制作的痰涂片与采用萋-尼（ZN）法在痰液采集后立即制作的直接涂片的效果。
对49例疑似肺结核患者的93份痰标本进行研究。其直接涂片（ZN涂片）采用热ZN法染色。然后将标本与苯酚硫酸铵碱性品红溶液混合，并在常温下保存。在第7天制作涂片（酚法涂片），然后进行脱色和复染以检测AFB（酚法）。ZN涂片和酚法涂片由专人盲法阅片。因各种原因排除18份标本后，对涂片阳性（3份直接涂片中2份阳性）患者的63份标本以及涂片阴性（3份直接涂片中3份阴性）患者的12份标本的酚法涂片和ZN涂片结果进行分析。ZN法为金标准。
涂片阳性患者的63份标本中，61份的酚法涂片和ZN涂片呈阳性，涂片阴性患者的12份标本中，11份的酚法涂片和ZN涂片呈阴性（kappa = 0.87）。酚法的灵敏度和特异度分别为96.8%和91.7%。
痰标本可在装有苯酚硫酸铵碱性品红溶液的痰容器中保存长达7天。然而，需要开展一项全面研究以证实酚法在将痰标本运送至显微镜检查中心检测AFB时的准确性。
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