Collection biomaterial in young children is always stressful for parents, which is often complicated by the unpredictability of children's physiological processes. If an adult can go to the toilet on a schedule, then the child’s body lives according to its own laws, and defecation can occur at the most inopportune time, for example, late at night or early in the morning, when the laboratories are still closed. In such situations, parents are faced with a natural and very important question about how long the biomaterial retains its diagnostic properties in the conditions of the refrigeration chamber.
Proper storage is not just a formality, but a critically important stage on which the reliability of the results directly depends. coprograms. The enzymes contained in stool continue to be active even after defecation, and if this process is not stopped by cooling or timely delivery, the composition of the sample will change. This can lead to false indicators of acidity, changes in the number of leukocytes or red blood cells, which, in turn, will lead to incorrect diagnosis and unnecessary treatment.
In this article we will analyze in detail what temperature regime is optimal, how to choose the right container and what time limits exist for various types of tests. Understanding these nuances will help you avoid a situation where the laboratory refuses to accept the material, or, even worse, when the analysis shows an error where the child is healthy.
Optimal storage periods for biomaterial
The main rule that all parents should remember: the ideal option is to deliver fresh, still warm biomaterial to the laboratory within 1-2 hours after defecation. However, in reality, especially when collecting from infants or when working evening shifts in clinics, this is not always possible. In such cases, the refrigerator comes to the rescue, which allows you to preserve the processes of decay and fermentation.
The average period during which feces for coprogram can be stored in the refrigerator is from 6 to 8 hours. At temperatures from +4 to +8 degrees Celsius, the main physical and chemical indicators remain stable. If more than 12 hours have passed, the material is usually considered unsuitable for research, since irreversible changes in the fiber structure and chemical composition begin.
⚠️ Attention: Never leave a container with biomaterial at room temperature for a long time. In warmth, bacteria begin to multiply at an exponential rate, which completely distorts the picture of intestinal microbiocenosis.
It is important to take into account the age of the child. In newborns, metabolic processes are faster, and the composition of stool can change more rapidly than in school-age children. Therefore, for infants, it is recommended to observe the minimum possible storage period, trying to get tested as soon as possible.
Correct temperature conditions
Temperature is a key factor in safety. In everyday practice, “refrigerated storage” often means different zones, and here lies a common mistake. It is strictly forbidden to place a container with biomaterial on a shelf near the back wall, where the temperature can drop to 0 or even -1 degrees. Freezing destroys cellular structures, and the analysis becomes uninformative.
The optimal place is the middle shelf of the refrigerator compartment or door (if there is a stable temperature of about +5...+6 degrees). It is in this range that the activity of enzymes slows down, but does not stop completely, which allows you to keep the sample in a condition suitable for research for an acceptable time.
If you use modern refrigerators with a system No Frost, you should be especially attentive to the circulation of cold air. Air flows can locally supercool objects, so it is better to place the container in a plastic bag or a special container to smooth out temperature changes and avoid direct contact with cold.
Selecting containers and preparing for collection
Not only hygiene, but also the safety of the sample depends on the container in which you collect the biomaterial. The use of glass jars of baby food or mayonnaise, even thoroughly washed, is now considered bad manners in laboratory diagnostics. Residues of detergents or microparticles of previous contents may enter into a chemical reaction with reagents.
Modern pharmacy containers are designed specifically for these purposes. They are sterile, made of chemically inert plastic and have a tight-fitting lid that prevents the sample from drying out and the penetration of foreign odors. For children, containers with a spoon-spatula built into the lid are often produced, which greatly simplifies the collection process.
Before collection, it is necessary to prepare a clean surface. The pot should be thoroughly washed with soap, rinsed with boiling water and dried. For infants who are not yet sitting on the potty, there are special sterile urinals or colostomy bags that are glued to the skin around the anus. Using a diaper to collect stool for coprogram is not recommended, since the absorbent gel instantly absorbs the liquid fraction, making analysis impossible.
☑️ Preparation for collecting biomaterial
Storage specifics for different types of tests
Coprogram is a general study, but Sometimes your doctor may order more specific tests and their storage requirements may vary. Understanding these differences will help you avoid mistakes. For example, an analysis for hidden blood or worm eggs may have its own nuances.
Below is a table that will help you navigate the shelf life of biomaterial for various studies:
| Type of analysis | Maximum time at room temperature | Maximum time in the refrigerator | Features |
|---|---|---|---|
| Coprogram (general) | 2 hours | 8 hours | Requires tightness |
| For eggs worms | 1 hour | 12 hours | Longer storage is allowed |
| For occult blood | 3 hours | 6 hours | Requires a diet for 3 days |
| Bacteriological culture | Not allowed | 2 hours (special Wednesday) | Only in sterile containers |
As can be seen from the table, bacteriological culture (bacteriological culture) requires special care. It often requires special transport media, and normal refrigeration storage may kill some of the bacteria, leading to a false negative result. In such cases, it is better to clarify the rules with the laboratory assistant in advance.
What should not be done with the sample
There are a number of actions that parents commit out of ignorance, trying to “save” the material, but thereby spoiling it. The most serious violation is freezing. Placing feces in the freezer is strictly prohibited. Ice crystals rupture the cell membranes, and after thawing you will get a homogeneous mass that is unsuitable for microscopy.
Also, you should not add water, preservatives (unless specifically provided by the laboratory) or other chemicals to the container. The feces must be native, that is, natural. An attempt to “dilute” dense stool with water will make it impossible to assess the shape and consistency, and will also change the specific gravity.
⚠️ Attention: Do not store biomaterial next to strong-smelling products (fish, smoked meats, spices). The plastic of the container can transmit odors, and volatile substances can change the chemical composition of the sample.
Another common mistake is collecting material from the toilet, even if it has been previously cleaned. The water in the toilet contains chlorine, residues of cleaning products and a lot of foreign bacteria, which is guaranteed to spoil the result of coprogram.
What to do if the child wears only a diaper with gel filler?
If there is no other way out, carefully collect only the top layer of feces, without touching the gel. But it is best to place clean cling film or a plastic bag in the diaper so that the feces remain on the surface and do not mix with the absorbent.
How to correctly deliver the test to the laboratory
After you have successfully stored the sample in the refrigerator, it is important to correctly deliver it to its destination. Sudden temperature changes during transportation are also undesirable. If it is hot summer or, conversely, severe frost, it is better to place the container in a thermal bag or wrap it in a towel.
When submitting an analysis to the registry, be sure to check whether they accept material that has been in the refrigerator all night. Some laboratories have strict internal regulations and may refuse to accept “yesterday’s” stool, even if it was stored correctly. Private clinics are often more flexible and equipped to handle material that has been sitting for up to 12 hours.
Remember to label the container correctly. The cover or special field must contain the child’s last name, first name and collection date. If you mix up the containers or forget the date, the laboratory technician has the right not to accept the analysis, since storage time is a critical parameter.
Frequently asked questions (FAQ)
Is it possible to freeze stool if it is not possible to donate it today?
No, you cannot freeze stool for coprograms. When frozen, the cellular structure is destroyed, salts precipitate, and microscopic examination becomes impossible. The analysis will have to be retaken.
Does the fact that the child ate beets or blueberries the day before affect the result?
Yes, some foods can color stool red or black, which can be visually mistaken for blood. Also, fatty foods can change the results for fat. It is better to ask your doctor about your diet in advance.
What to do if the light in the refrigerator is turned off?
If the refrigerator is not opened, it keeps cold for several hours. If the shutdown is long and the temperature inside has risen above +10 degrees, it is better not to use the material, since bacteria could be activated.
Is it possible to collect stool in the evening and hand it over in the morning the next day?
Yes, this is a valid option if the period of time does not exceed 8-10 hours and the container has been in the refrigerator at the correct temperature all this time.