Only with a peak flow monitor can modern asthma control plans be followed. The monitor gives the patient better, earlier and more objective information, to find breathing problems before wheezing and coughing begins.

Physicians typically recommend taking one measurement in the morning and one in the evening on a daily basis. Measurements should also be taken when feeling poorly or experiencing shortness of breath. Always take measurements before inhaling any prescribed drugs.

Your physician is only interested in the HIGHEST peak flow value achieved during a measurement session. Please repeat the measurements until you feel you have gotten the best possible result for that session. In the event of declining results at each successive measurement, talk to your doctor. It may be a sign of unstable asthma. 

Coughing during a measurement can produce erroneously low results so always repeat the measurement. If you want to perform continuous measurements sequentially, be sure to have sufficient relaxation after each measurement to ensure accurate results. 

Please note that low peak flows indicate a pending asthma attack even though no symptoms are felt! 

• Measurements can be performed while standing, or sitting upright.
• For better comparability of your data you should always perform the measurement in the same position.
• Hold the monitor with both hands.
• Inhale deeply and hold your breath for a moment.
• Cover the mouthpiece tightly with your lips.
• Exhale into the measuring tube as strongly and quickly as possible!
• Take the monitor away from your mouth and see your result in the display.
• It is recommended that three or more measurements be taken sequentially.

The «traffic light scheme» allows a patient to self-assess measured values to follow the progression of the illness. Self-assessment empowers patients to control their asthmatic illness in close co-operation with their physician.

• Green area: the lung disease is well under control.
• Yellow area: the medication dosage should be increased according to the physician's recommendation.
• Red area: dangerous! The patient should act as recommended by the physician or seek emergency medical treatment. 

Microlife PF100 device is used to measure «Peak Expiratory Flow» (PEF) and Forced Expiratory Volume in 1-second (FEV1) in both children and adults.

• PEF is the fastest speed air can be blown out of the lungs after inhalation.
• FEV1 measures the volume after exhaling in 1-second.

Peak Flow (PEF) and Forced Expiratory Volume in 1-second (FEV1) measurements can tell how well lungs are breathing by monitoring airflow. Doctors can have patients monitor changes in airflow and record the results. The automatic memory stores and provides easy access to the last 240 readings along with the time and date. 

The «traffic light scheme» allows a patient to self-assess measured values to follow the progression of the illness. Self-assessment empowers patients to control their asthmatic illness in close co-operation with their physician. The physician determines a green, a yellow and a red area for the patient's peak flow readings and determines the patients own personal best value. This is the highest value the patient can achieve under optimum conditions (free of symptoms, feeling well). [Example: 500 l/min.]

• The green area usually reaches 80 percent of the personal best value. [Example: 500 l/min x 0.8=400 l/min]
• The yellow area usually reaches 60 percent of the personal best value. [Example: 500 l/min x 0.6=300 l/min].


As long as the values are in the green area, the lung disease is well under control. If the readings are frequently in the yellow area, the medication dosage should be increased according to the physician's recommendation. Peak flow results in the red area are dangerous! The patient should act as recommended by the physician or seek emergency medical treatment. 

Our PF100 Peak Flow meter is designed to be used to compare the user's test values of PEF and FEV1 in relation to their personal best values. 


The first step is to have the patient tested for example in a spirometer, to get a complete monitoring of his/hers condition of the lungs. Then the best values can be entered via Microlife Asthma Analyzer SW into the persons PF 100, thus enabling the use of the "traffic lights" and showing the patient easily and clearly visible at what condition hers/his lungs are.