"Lab values" is an app for and by clinicians to be able to interpret laboratory results in a correct and easy way in the workplace. Important and commonly used lab values are discussed. In addition to interpretation of a deviating lab value, issues such as pitfalls and limitations are also discussed and background information is given in-depth. "Lab combinations" such as anemia, iron status and the Addison crisis are explained as support in choosing the right lab determinations. Calculators have also been added to the app with which, for example, a corrected calcium or anion gap can be calculated. This app is indispensable for every healthcare professional!