Proper specimen collection is a crucial step in the conduct of a study or experiment especially in creating science projects; it is a vital aspect in the practice of scientific medicine and in microbiology. In it rests the validity of each succeeding step; with the definition of the diagnosis and nature of diseases, the microbiologic investigation determines the mode of treatment and outlook for an affected patient.

In the collection of any specimen for science projects or any microbiologic examinations, especially for observations using the microscope, it is important to remember some ground rules. Remember to collect the specimen from the actual site of disease. Do not contaminate it with microbes from nearby areas. For instance, in making smears and cultures from ulcers in the throat, be very careful to take the specimen from the actual site of ulceration and not contaminate it unduly with secretions of the mouth. Always use sterile equipment and materials to collect the specimen. Also place the specimen in a sterile container. Sterilize material used in collecting the specimen as soon as possible.

Take the necessary precaution in the collection of the specimen. Be sure to collect the specimen in such a manner as not to endanger others. Sputum or other excreta must not soil the outside of the container. Take great care in handling specimens collected in cotton-plugged tubes. Cotton plugs can entirely soak up a small specimen. Also microbes from the environment can pass through wet plugs and contaminate the specimen.

Whenever possible, make smears direct from the original specimen. Do not add any preservative or antiseptic to the specimen. Otherwise, the result of the science project examination will not be valid. If possible, take the specimen before the patient has received any antimicrobial drug or before the patient’s wound has had local treatment. If the patient has already received an antimicrobial drug, notify the laboratory.

Make sure to label and identify the specimen properly. Be careful not to mislabel and exchange specimens. Give the patient’s name, identification number, source of the specimen, date of the month, time of day specimen was taken, doctor’s name, as well as tentative diagnosis.

Deliver the specimen to the laboratory promptly. The person delivering the specimen to the laboratory may have to care for the specimen in instances where the laboratory personnel are off duty temporarily. In this event specimens already inoculated onto culture media are placed in the incubator. On the other hand, specimen not on culture media are placed in the refrigerator. When cultures must be made without delay, the medium chosen should be that most likely to grow the suspected organisms, as well as other microbes that might be present. Since it supports the growth of microorganisms better than most other culture media found in the usual microbiologic laboratory, blood agar is generally used. Blood agar plates are superior to cubed media except in those instances in which the cultures must be shipped a distance to the diagnostic laboratory. Plates are not easily transported.