More spirometric analysis needs to be performed in order to discover lung diseases like chronic obstructive pulmonary disease (COPD). A mini spirometer can quickly and easily be used for screening. Today, a plethysmograph is used at the hospital in Helsingborg at the department of clinically physiology. However, they also have a mini spirometer, which is seldom used. By comparing the mini spirometer with the reference (the plethysmograph), results may indicate whether it could be possible to use the mini spirometer for screening or in other situations at the department when immediate and reliable information about lung function is needed. As a total of 45 patients participated in this study. All were examined with the mini spirometre after the conventional spirometry using a reversibility test. Of these there were 41 who were used in the study. After the conventional spirometry, they performed 4 - 7 forced expirations followed by inspirations. Theparameters investigated were FVC (forced vital capacity), FEV1 (forced expiratory vital capacity in 1 second), and FEV1/FVC. For the conventional spirometry slow VC was used, according to clinical routine. With 95 % CI the mean ・} SD was calculated to be for FVC between the 2 methods -0,19 ・} 0,30 litre. For FEV1 the results were 0,04 ・} 0,13 litre and for FEV1/FVC 0,05 ・} 0,05 litre. Paired t-test resulted for FVC in t = 4,1. FEV1 gave t= 1,79 and for FEV1/FVC was t= 6,28. The t-values were compared with t critical= 2,03 which were taken from a table. A lower t- value than t critical suggests that the methods are comparable. When comparing the difference between the both methods, FEV1 agreed well, while FVC and FEV1/FVC was too large. / Fler spirometrier behover genomforas for att upptacka lungsjukdomar som t.ex. kronisk obstruktiv lungsjukdom (KOL). En minispirometer kan snabbt och enkelt screena for detta. Pa Helsingborgs lasarett pa avdelningen for klinisk fysiologi anvands rutinmassigt enbart en plethysmograf-spirometer, trots att det dar aven finns en minispirometer. Genom att undersoka hur noggrann minispirometern ar jamfort med den vanligtvis anvanda spirometern, kan den lilla varianten i vissa fall anvandas vid t.ex. screening eller i samband med andra undersokningar dar information om lungfunktion behovs. Sammanlagt stallde 45 konsekutiva patienter upp pa analys via minispirometri efter genomford konventionell spirometri med reversibilitetstest. Av dessa anvandes 41 stycken i undersokningen. Efter den konventionella spirometrin fick de utfora 4 - 7 forcerade expirationer direkt foljt av inspirationer. De parametrar som anvandes var forcerad expiratorisk volym under den forsta sekunden (FEV1), forcerad vital kapacitet (FVC) och kvoten FEV1/FVC. For den konventionella spirometrin anvandes langsam VC enligt klinisk rutin. Med 95 % KI beraknades medelvardet och SD for skillnaden i FVC mellan de bada metoderna till -0,19 ・} 0,30 liter. For FEV1 var resultatet 0,04 ・} 0,13 liter och kvoten FEV1/FVC gav 0,05 ・} 0,05. Parat t-test gav for FVC t= 4,1. For FEV1 t= 1,79 och for kvoten FEV1/FVC t= 6,28. T- vardena jamfordes med t kritiskt = 2,03 som erholls ur en tabell. Ett lagre t- varde an tkritiskt antyder att metoderna ar tillrackligt lika. FEV1 stamde bra overens mellan de bada metoderna. Det fanns en signifikant skillnad for FVC och forkvoten FEV1/FVC.