Sputum cytology is a medical test in which a sample of sputum (mucus) is examined under a microscope to determine whether abnormal cells are present. Sputum is different from saliva, and is produced in the lungs and the airways leading to the lungs. A sample may be obtained either by the person coughing up mucus at home or in the doctor’s office or during a bronchoscopy, a procedure which allows the doctor to look inside the lungs’ airways at the same time a sample is taken.
There is no special preparation necessary if samples are to be taken at home or in the doctor’s office. In these instances, three samples are usually collected over a period of three days. If you will be collecting the samples at home, your doctor will give you a receptacle containing a small amount of fixative which helps to preserve the samples. After the samples have been collected, follow your doctor’s instructions about when and where to return them.
It is best to collect the samples first thing in the morning. To obtain the best results you should:
- Remove dentures if you wear them.
- Rinse your mouth with water.
- Take about four deep breaths followed by a few short coughs, then inhale deeply and cough forcefully into the container. Make sure to get a sample from deep in your airway.
If mucus samples are to be taken during a bronchoscopy, your doctor will ask you to sign a consent form since this procedure generally takes place in a hospital or clinic and requires some anesthesia. Be sure that before signing the form, you discuss with him/her any concerns you might have regarding the need for the test, how it is done or any potential risks involved. Your doctor will ask about any medicines you are taking, both prescription and over-the-counter, any allergies you might have or whether you have experienced any bleeding problems or take blood thinners. In preparation for the test, you will be told how soon before the actual procedure to stop eating and drinking. Be sure to follow the exact instructions given by your doctor. Since the medication you will be given prior to the procedure will make you sleepy it is best to arrange for a ride home.
Once the samples are obtained, they will be sent to a laboratory for analysis. It may take up to several days to receive the results of sputum cytology. Unfortunately, there is a chance of false-negative test results, meaning that the test may indicate a lung condition is not present, when in fact, it is. If symptoms continue in the absence of a diagnosis, further testing may be necessary.