Collection of biomaterial from a small child often turns into a real test for parents. The baby may go to the toilet at inconvenient times, for example, late at night or early in the morning, when the laboratory is still far away. At such moments, moms and dads are faced with a pressing question: is it possible to store the sample until the morning and how to do it correctly so as not to spoil the diagnostic results.
Modern medicine requires high precision, and improper storage can distort data about the health of the baby. The refrigerator is the only acceptable place for temporary storage of biomaterial, but even here there are strict time limits. Violation of the temperature regime or overexposure of the sample leads to the proliferation of bacteria, which normally should not actively multiply in feces.
In this article we will analyze in detail how long it is permissible to keep the container on the shelf, how cold affects various types of research and why compliance with these rules is critical for making the correct diagnosis of your child.
The effect of low temperature on biomaterial
Low temperature slows down biochemical processes, but does not stop them completely. When you place a container with biomaterial in the refrigerator, you inhibit the proliferation of opportunistic microflora, which is always present in the intestines. However, enzyme activity is preserved, and prolonged exposure to cold can change the pH environment, which will make it impossible to accurately determine hidden blood or some chemical indicators.
Living organisms, such as Giardia or amoebas, are especially sensitive to temperature changes. If the purpose of the analysis is to search for living forms of parasites, then storage even in the cold can be disastrous. In such cases, laboratory technicians recommend delivering the material warm, since when cooled, the cysts may become deformed or die, which will lead to a false negative result.
⚠️ Attention: Freezing feces in the freezer is strictly prohibited! Ice crystals destroy the cellular structure of the sample, making the analysis completely useless.
For most standard tests, such as coprogram or test for worm eggs, refrigeration is an acceptable and even recommended method of preservation if delivery to the laboratory takes more than 2-3 hours. The main thing is to ensure a stable temperature regime without sudden changes.
Optimal storage periods for different tests
The time during which the biomaterial remains suitable for research directly depends on the type of test prescribed by the doctor. There is no universal answer “for all cases”, so it is important for parents to know the specific requirements for each type of diagnosis.
The most demanding in terms of freshness is the analysis for dysbacteriosis. Here the count literally goes on for hours, since the composition of the microflora begins to change immediately after defecation. Ideally, such material should be delivered to the laboratory within 2-3 hours. If this is not possible, storage in the refrigerator at a temperature of +2 to +4 degrees Celsius is allowed, but no more than 6-8 hours. After this period, colonies of bacteria begin to grow or die, distorting the real picture of the state of the intestines.
For research on worm eggs and protozoa the requirements are a little less stringent, but also have their limits. Storage in a cool place for up to 12 hours is allowed, but up to 8 hours is considered optimal. Long-term storage can lead to the fact that the egg shells become less noticeable under a microscope or, conversely, the development of larvae will begin, which will complicate the identification of the type of parasite.
If prescribed coprogram (general stool analysis), then the material retains its properties the longest. In a tightly closed sterile container at a temperature of +4°C, it can be kept for up to 12 hours without significant changes in physicochemical properties. However, for the analysis of occult blood, the time frame may be reduced, since red blood cells begin to break down in an acidic environment.
| Type of analysis | Maximum time at room temperature | Maximum time in the refrigerator (+2...+4°C) | Criticality of conditions |
|---|---|---|---|
| For dysbiosis | 2 hours | 6-8 hours | High |
| For eggs worm | 4 hours | 10-12 hours | Average |
| Coprogram | 6 hours | 12 hours | Low/Medium |
| For occult blood | 3 hours | 6-8 hours | High |
Rules for choosing a container and preparation
The quality of the research depends not only on time, but also on what the material is collected in. The use of inappropriate containers, such as matchboxes or plastic yoghurt pots, is not acceptable. Such containers are not sterile and may contain residues of substances that will react with reagents in the laboratory.
For collection, you must use special pharmacy containers. They are made of medical plastic, which is chemically inert and does not affect the composition of the biomaterial. The lid of such containers is equipped with a special spoon-spatula, which makes it easier to remove the required amount of material without touching the walls of the container with your hands.
- 🧪 Sterility: The container must be absolutely clean and dry. You cannot wash it yourself and reuse it, even if it seems clean.
- 🌡️ Temperature: Before collection, it is better to keep the container at room temperature so that cold plastic does not “burn” the sample when it comes to searching for living forms.
- 🚫 Isolation: The lid must close tightly, until it clicks, to prevent air from entering and moisture evaporating, which changes the consistency.
If a child goes to the potty, he must also be carefully prepared. The pot is washed with soap, rinsed with boiling water and dried. However, it is best not to collect material directly from the surface of the pot, especially if it is plastic. The best option is to put clean cling film over the potty or put a disposable plastic bag inside so that the feces do not touch the walls.
Collection technique for children different ages
Collecting analysis from an infant and a preschool child are two different scenarios that require a special approach. In infants, defecation often occurs immediately after feeding, and catching this moment is the main task of parents.
For infants who are not yet sitting, it is convenient to use the oilcloth collection method. Place a clean, ironed diaper or disposable absorbent diaper (smooth side up) under the baby's bottom. As soon as the child has gone to the toilet, the material is carefully collected from the container with a spoon. It is important to take a sample from different places: from above, from the side, from the middle, especially if mucus or veins are visible.
With older children who already use the potty, the process is simpler, but requires hygienic preparation. The pot must be clean, without traces of detergents. If a child is afraid or embarrassed, do not rush him, as stress can cause constipation or, conversely, diarrhea.
⚠️ Attention: Never collect feces from the fabric surface of a diaper or diaper! The fabric instantly absorbs the liquid fraction, leaving only dense particles on the surface, which will disrupt the ratio of elements and distort the result.
The amount of material also matters. For most tests, a volume of one to two teaspoons (approximately 5-10 grams) is sufficient. If you collect too little, the laboratory technician may not have enough material to conduct all the necessary tests.
Transportation and delivery to the laboratory
Even if you collected and stored the material correctly, the transportation stage can ruin everything. In summer or in a hot room, the temperature inside the container rises quickly, triggering fermentation processes. In winter, on the contrary, the sample may become hypothermic if it is carried in a bag without thermal protection.
For transportation, it is best to use a thermal bag or a regular bag with refrigerant (cooling element), which is often placed in boxes with products. This will help maintain a stable temperature throughout the journey. Do not leave the container in the car in direct sunlight or near operating heating devices.
☑️ Checklist before leaving home
In the laboratory, be sure to notify the registrar about the time of collection of the biomaterial. This will help laboratory technicians correctly interpret the results, taking into account possible changes in the properties of the sample during storage.
Common mistakes of parents during storage
The desire to do everything right sometimes leads to mistakes that nullify efforts. One of the most common mistakes is storing in the “fresh zone” or on the refrigerator door. The temperature there often fluctuates due to the opening of the door, which does not provide stable conditions.
Another mistake is using unsterile containers “just in case.” Parents can collect the material in a jar, then figure out what was needed in the container and transfer it. When transferring, sterility is violated, and foreign bacteria from the air or hands enter the sample.
Is it possible to store feces in the freezer?
No, it is not possible. Freezing destroys the cellular structures of bacteria and parasites. After defrosting, you will simply get an organic mass, unsuitable for microscopic and bacteriological examination. Analysis will show the absence of life where it was, or the presence of non-existent artifacts.
Ignoring consistency is also a mistake. If the stool is too dense or, conversely, watery, this must be taken into account. Watery stool loses its properties more quickly, and its storage time should be reduced to a minimum.
When the result may be incorrect
Understanding when the result may be false will help you avoid repeated tests. If the sample is stored longer than the required time, the number of bacteria in it can increase significantly, which will be regarded as dysbacteriosis or an intestinal infection, although in fact the child is healthy.
During long-term storage, leukocytes and red blood cells are destroyed. If the test for occult blood or inflammation used old material, the result will be negative, even if the problem exists. This can lead to missing a serious disease.
- 🦠 Growth of extraneous flora: If the seal is broken, bacteria from the air enter the sample.
- 💧 Change in humidity: Evaporation of moisture makes the stool dry, which interferes with the identification of helminth larvae.
- 🧪 Chemical changes: Enzymes continue to break down proteins and fats, changing the chemical composition.
Therefore, the rule “fresh means best” works flawlessly here. If you doubt the quality of the stored material, it is better to retake the test than to treat the child for a non-existent diagnosis.
What to do if the child went to the toilet at night?
If a bowel movement occurred at night, collect the material in a sterile container, close it tightly and place it in the refrigerator (on the middle shelf, not against the back wall). In the morning, immediately after waking up, take him to the laboratory. The main thing is that no more than 8-10 hours have passed since collection for standard tests.
Is it possible to collect the test in the evening and submit it in the morning?
For analysis of worm eggs and coprograms - yes, it is possible, if you ensure storage at a temperature of +2...+4°C for no more than 10-12 hours. For dysbacteriosis analysis, evening collection is not recommended, since the composition of the flora will change overnight.
Does it need to heat the container before donation?
No, there is no need to specifically heat the material. Sudden temperature changes can cause moisture to condense inside the container. You just need to take it out of the refrigerator and carry it in your bag. In the laboratory, samples are adapted to room temperature during the preparation process.
Does the child’s diet the day before affect shelf life?
Diet does not have a direct effect on shelf life, but it does change the composition of feces. Fatty foods can speed up oxidative processes, and an abundance of fiber can speed up fermentation. Therefore, compliance with the shelf life for “heavy” stools becomes even more critical.
Can wet wipes be used for collection?
Absolutely not. Wet wipes contain fragrances, alcohols and antiseptics, which will kill beneficial microflora and distort chemical analysis. You only need to collect it with a clean spatula from the container.