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Collecting Samples for Testing

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Samples that are Naturally Eliminated

Some samples such as urine, feces, and sputum can be collected as the body naturally eliminates them, while semen can be collected by the patient. Collection of some samples from young children or patients with physical limitations may require assistance. Usually, collecting these samples is painless, but obtaining them can occasionally be awkward and unpleasant because they involve elimination of bodily wastes and involve body parts and functions people prefer to keep private.

Sometimes these types of samples can be collected at home and brought to a medical office or facility, but they also may be collected at a medical facility such as a doctor's office, clinic, laboratory patient service center, or hospital. These facilities are usually designed to minimize sample handling by the patient and embarrassment. You may, for example, find a "pass-through" window in the bathroom so you don't have to walk the hall with a see-through container you have just filled. You may find printed instructions on how to obtain urine or stool samples posted in the bathroom so you don't have to listen to a nurse tell you explicitly how to obtain a "clean catch" of urine or a fecal sample. If you are sensitive to these issues and want to choose a healthcare provider or testing center that provides such options, you can ask about their procedures, their layout, and steps taken by the staff to ensure patient privacy and comfort.

Below are examples of types of samples typically collected by the patient. It is very important that all instructions for sample collection are carefully followed. Make sure you understand the instructions before collecting your specimen.

Semen — Male patients ejaculate into a specimen container, avoiding lubricants, condoms, or any other potentially contaminating materials. Usually, men need to refrain from ejaculating for at least 2 days prior but less than 7 days before collecting the specimen. The specimen must not be refrigerated but kept as close to body temperature as possible by placing the container in a pocket and delivering it to the laboratory within 60 minutes.

Sputum — Patients are instructed to cough up sputum from as far down in the lungs as possible. (A health practitioner may assist the patient in some situations.) This is best accomplished first thing in the morning before eating or drinking, by taking several deep breaths before expectorating into the collection cup. Sputum should be relatively thick and not as watery as seen when producing saliva.

Stool — Patients usually collect this sample themselves during toileting, following instructions to prevent the sample from becoming contaminated from other material in the toilet bowl. Patients may also be told to avoid certain foods during the test period. Depending on the test, patients may be instructed to collect the sample in a container, scoop a small portion into a vial, or smear a small amount on special test paper. Wash your hands well after handling the sample.

Urine — Most urine specimens are collected by having the patient urinate into a container or receptacle. To keep the sample from becoming contaminated by materials outside the urinary tract, patients are given instructions on how to clean the genital area and void a bit of urine before collecting the specimen into the container. (If a urinary catheter is required, a health practitioner is usually responsible for insertion.) Collecting the urine specimen is awkward but not in itself uncomfortable (An infection, however, can create a burning sensation during urination.). For certain tests, 24-hour urine samples are collected at home and must be refrigerated during the collection process. Remember to wash hands well after collecting the specimen.

Saliva — This type of sample may be collected using a swab or, if a larger volume is needed for testing, patients may be instructed to expectorate into a container without generating sputum.

Oral fluid — This is a combination of saliva and oral mucosal transudate (material crossing the buccal mucosa from the capillaries) that is also collected from the mouth. For example, a rapid HIV test uses oral fluid. The patient collects the sample by using a special device to swab around their outer gums.

Sweat — This type of sample may be collected using a special sweat stimulation procedure that is painless and allows sweat to be collected into a plastic coil of tubing or onto a piece of gauze or filter paper. It is then analyzed for the amount of chloride in the sweat. Elevated levels of chloride suggest a diagnosis of cystic fibrosis.

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