fig1 illustrates a first embodiment of the diagnostic tool according to the present invention . the diagnostic tool 10 comprises a housing preferably made of synthetic resin or any other suitable material . the device comprises a display 2 as for example a liquid crystal display ( lcd ) and manual input means 4 , 4 a . after starting operation of the diagnostic tool pre - defined questions significant for the probability of the occurrence of the disease like copd as for example the question “ are you currently smoking ?” are displayed on the display means 2 . the selection of the diagnostic questions will be discussed in more detail later . the user , a physician , case manager or patient , can then respond to the question by moving a cursor between a “ yes ” and a “ no ” field by means of a scrolling wheel 4 a and confirming the respective response by pressing input - or enter - button 4 . the arrangement of button 4 and scrolling wheel 4 a allows a single - handed operation of the diagnostic tool 10 . in order to avoid the necessity of battery replacement photovoltaic cells 7 and a suitable capacitor ( not shown ) are provided as power source . when the user has responded to a diagnostic question by pressing button 4 the next question is shown on display 2 . the user then again inputs his response until an answer to the last question has been given by the user . the final result is then calculated as will be explained in more detail later and displayed on a display device 2 . instead of yes - or no - questions it is also possible for a user to choose among a plurality of different responses by navigating between different response fields using the scroll wheel 4 a . on the question “ what is your age ?”, the user could for example choose between response fields “ under 40 ”, “ 40 to 49 ”, “ 50 to 59 ”, “ 60 to 69 ”, “ 70 or older ”. the functional units of the diagnostic tool 10 are shown in the block diagram of fig2 . a processor 6 controls the operation of display unit 2 and input unit 4 , consisting e . g . of button and scroll wheel or any other suitable input device . in addition , processor 6 , which may be a well - known microprocessor device , controls memory 8 on which the predefined questions and the predefined tables as the transformation table shown in fig5 and the result table of fig6 are stored in a non - volatile memory section and the interactively given responses and the current count value are stored in a dynamic memory section . moreover , the processor 6 performs the calculation of the count value and the assignment of the diagnostic prognosis based on the final count value . the operation of the diagnostic tool 10 according to the present invention is as follows : the user starts operation by pressing the input button 4 or a separate start key . processor 6 then controls the display unit 2 to display the first question like e . g . “ what is your age ?”. the user then gives his response by navigating a cursor by navigation wheel 4 to the corresponding response field and confirming the input by pressing confirmation button 4 . then , on the display 2 the next question is shown , for example a yes / no - question like “ are you currently smoking ?”. the user then has to choose either the “ yes ” or “ no ” response symbol . the next question may be about the smoking history of the patient . this question consists of two parts , namely the average smoking intensity in cigarettes per day and the total smoking time in years . after the user has input the corresponding responses by “ clicking ” on the corresponding response fields the count value corresponding to the smoking history is calculated by processor 6 using a transformation table as shown in fig5 . in vertical direction the average smoking intensity and in horizontal direction the total smoking time is given . the count value corresponding to the smoking history of a patient can then be taken from the respective element of the table shown in fig5 . typically some questions about subjective disease symptoms of the patients follow including being short of breath , occurrence and quantity of phlegm , and / or the occurrence of chest wheezing or whistling . to each response a corresponding count value is assigned , which count value may also be a negative value . processor 6 performs a summation of all count values and calculates a final count value as result when the response to the last question has been input by the user . the final count value is then translated into a diagnostic prediction using a result table an example of which is shown in fig6 . a final count value of 16 to 19 for example corresponds to a copd probability of 40 % and a count value of between 24 and 27 a copd probability of about 80 %. high percentage values suggest further , more detailed a diagnosis of the patient . the selection of the diagnostic questions , the transformation of the responses into account values and the diagnostic prognosis values of the result table are the result of extensive clinical studies . in these studies the predictive ability and statistical significance of a plurality of selected question items have been investigated . for identifying copd ( case finding ) the following questions showed statistically significant relation with spirometric results ( post - bronchodilator fev1 / fvc & lt ; 0 , 70 ). in a study the following questions achieved sensitivities of 58 . 7 %- 80 . 4 % and specificities of 57 . 5 %- 77 . 0 %, depending on the scoring system used . predictive values range from 30 . 3 %- 37 . 0 % for a positive test and 89 . 0 %- 92 . 7 % for a negative test . age group ( in years ); pack - years smoked (“ how many cigarettes do you currently smoke each day [ if you are an ex - smoker , how many did you smoke each day ]?” and “ what is the total number of years you have smoked cigarettes ?”); body mass index ( calculated from height and weight ); weather affects cough (“ does the weather affect your cough ?”); phlegm without a cold (“ do you ever cough up phlegm [ sputum ] from your chest when you don &# 39 ; t have a cold ?”); phlegm in the morning (“ do you usually cough up phlegm [ sputum ] from your chest first thing in the morning ?”); wheeze frequency (“ how frequently do you wheeze ? ); and have had any allergies (“ do you have or have you had any allergies ?”). for differentiating copd and asthma a similiar study found the following 9 questions showing statistically significant relationships with obstruction . this candidate questionnaire achieves sensitivities of 53 . 8 %- 83 . 3 % and specificities of 58 . 8 %- 88 . 2 %, depending on the scoring system used . predictive values range from 60 . 7 %- 77 . 8 % for a positive test and 71 . 4 %- 82 . 2 % for a negative test : age group ( in years ); pack - years smoked (“ how many cigarettes do you currently smoke each day [ if you are an ex - smoker , how many did you smoke each day ]?” and “ what is the total number of years you have smoked cigarettes ?”); recent cough (“ have you coughed more in the past few years ?”); breathing - related work loss (“ during the past 3 years have you had any breathing problems that have kept you off work , indoors , at home , or in bed ?”); hospitalization for breathing (“ have you ever been admitted to hospital with breathing problems ?”); recent breathlessness (“ have you been short of breath more often in the past few years ?”); quantity of phlegm (“ on average , how much phlegm [ sputum ] do you cough up most days ?”); cold usually goes to chest (“ if you get a cold , does it usually go to your chest ?”); and the resulttable may preferably based on a scoring system using two cut - points intended to place the persons within one of three zones : persons with a high likelyhood of having obstruction ( high pridictive value of a positive test ; red zone ), persons with a low likelyhood of obstruction ( high priductive value of a negative test ; green zone ) and an intermediate zone ( yellow zone ). based on the above - mentioned questions and the 3 - zone scoring system an example of a questionnaire and the corresponding result table ( scoring ) for case - finding as well as a differential diagnosis against asthma is given in the following table 1 . a final count value of more than 55 ( 60 ) corresponds to the red zone , values between 21 and 54 ( 36 and 59 ) to the yellow zone and final count values below 20 ( 35 ) correspond to the green zone . according to the present invention the functions of identification of copd and differntial diagnosis are preferably integrated within one tool . further embodiments of the diagnostic tool according to the present invention are shown in fig3 and 4 . fig3 illustrates a diagnostic tool 20 comprising a casing incorporating the display , processor and input units of the device as well as means ( 21 ) for holding a prescription pad and possibly a pen for the physician . as shown in fig3 , diagnostic tool 20 may be operated by two input units 4 , one for navigation and one for input confirmation similarly to the input device of a laptop computer . alternatively , the functionality of the diagnostic tool my be incorporated in a laptop computer , a smart phone or organiser 30 as shown in fig4 . as a further alternative , the diagnostic tool according to the invention may be embodied as a mechanical device .
a diagnostic tool for pulmonary diseases comprises a display unit for displaying predefined diagnostic questions relating to the pulmonary disease and for outputting a diagnostic prognosis on the disease , an input unit for receiving responses from a user to the diagnostic questions displayed on the display unit , a storage unit for storing the predefined questions and the interactively input responses , a calculation unit for assigning each received response a predetermined count value , adding up the count values obtaining a final count value , assigning the final count value the diagnostic prognosis using a pre - defined result table stored in the storage unit . the diagnostic tool according to the present invention allows the general practitioner or the patient to carry out a fast first diagnosis on functional lunge disease , in particular copd . if a high probability , for example in percentage points , is established , further , more detailed diagnostic steps may be undertaken .