The employer must not permit an employee to work without a current medical opinion stating that there are no contraindications to work at the defined work post (article 229, § 4  of the Labour Code)

The medical opinion is issued in the form of a certificate, which the examining doctor issues to the employee and employer.

The employer who disagrees with the content of a certificate that is issued may apply within 7 days of the certificate issue date to the doctor who issued it to repeat the examination.  The examination should be carried out within 14 days of the date of submission of the request.  The medical opinion issued on the basis of his opinion is final.

Preventive examinations:

Are carried out on the basis of a note issued by the employer which should contain:

• A definition of the type of prophylactic examination that is to be conducted,
• In the case of newly employed workers or workers being transferred to another work post - a definition of the work post in which the person is to be employed; insofar as the employer may indicate two or more work posts, in the instructions that reflect the company’s needs,  
• In the case of workers - a definition of the work post in which the worker is employed,
• Information on the presence of harmful substances at the work post or work posts specified in points 2 and 3 or arduous conditions, as well as the current results of tests and measurements of the substances that are harmful to the health, which have been conducted at these work posts.

Types of examinations (art. 229 §§ 1-3, 5 k.p.):

• Preliminary examinations, to which the following are subject:
  - newly employed workers,
  - youth workers transferred to another work post
  - other workers transferred to other work posts where there is a presence of
  substances that are harmful to the health or arduous conditions.
  
  People who are re-employed by a given employer to the same position or to the same working conditions are not subject to such examinations.
• Periodic examinations, to which the following are subject:
  
  • all currently employed workers (in strictly defined deadlines, as specified by the appropriate doctor in consultation with the employer)  
  • workers employed in conditions that expose them to the actions of carcinogenic substances and agents or dust causing fibrosis:
    • after stopping work in conditions where they are in contact with such substances, agents or dust
    • after termination of the employment relationship, if the interested party requests such examinations
• control examinations, to which the following are subject:
  
  • workers, whose incapacity to work has been caused by chronic sickness lasting longer than 30 days.

The detailed principles for conducting medical examinations for workers, the prophylactic scope of the health care over workers and medical opinions are defined in the Regulation of the Minister of Health and Social Welfare of 30 May 1996  on conducting medical examinations of workers [...], (Journal of Laws of 1996, no. 69, item 332)

The cost of the examinations and other costs of prophylactic health care of workers that are required as a result of the working conditions are borne by the employer (article 229 § 6 of the Labour Code)