Collecting biomaterial for laboratory research in young children often turns into a real logistics operation for parents. When it comes to o coprogram or occult blood testing, it is critical to maintain not only sterility, but also the time frame for delivering samples to the laboratory. Many mothers and fathers are wondering whether it is permissible to postpone going to the clinic until the next morning if the child had a bowel movement late in the evening.
Modern medicine gives clear answers, but they depend on the type of study ordered. Universal Rule there is no test for all types, since different microorganisms and chemical compounds behave differently when the temperature drops. Understanding these nuances will help to avoid false diagnoses and the need for a repeated, often stressful for the child, collection procedure.
In this article we will look in detail at how to properly preserve a sample if immediate delivery is not possible, and what mistakes most often lead to damage to the biomaterial. You will learn why freezing is strictly prohibited, and how temperature conditions affect the reliability of the result.
Factors influencing the safety of biomaterial
The main enemy of a fresh sample is time. Immediately after defecation, bacteria begin to actively multiply in the masses, which normally live in the intestines, but change their activity outside its environment. This leads to a change pH environment and the chemical composition, which makes the analysis for dysbiosis or carbohydrates completely uninformative after a few hours.
The refrigeration chamber acts as a brake for these processes. At temperatures from +2 to +8 degrees Celsius, metabolic processes in bacteria slow down, but do not stop completely. That is why, even in the cold, there are strict time limits, violation of which is tantamount to obtaining a false result.
⚠️ Attention: Never use the fast freezing mode or the freezer to store feces. Ice crystals destroy the cell walls of bacteria and helminth eggs, making them invisible to the microscope.
The second critical factor is the tightness of the container. If the container is not tightly closed, the sample will dry out, and some chemical compounds may oxidize when exposed to air. For collection, it is best to use special sterile containers with a spoonsold in pharmacies, as they provide the necessary isolation from the external environment.
It is also important to consider the density of the material itself. Liquid stool (diarrhea) deteriorates much faster than formed stool, since water is an ideal environment for the rapid proliferation of pathogenic flora. In such cases, a delay of even one hour can play a decisive role.
Storage periods for various types of analyzes
The answer to the question about storage time directly depends on what exactly the laboratory technician is looking for. Different studies require different conditions, and they should absolutely not be confused. Below is a table systematizing the permissible time intervals for the main types of diagnostics.
| Type of analysis | Maximum time at room temperature | Maximum time in the refrigerator (+2...+4°C) | Features |
|---|---|---|---|
| Coprogram (general) | 2-3 hours | Up to 8-12 hours | Overnight storage is acceptable if tightly closed |
| For occult blood | 3 hours | Up to 6 hours | Requires a strict diet before delivery |
| For dysbacteriosis | 1 hour | Up to 3 hours (with transportation in the cold) | The faster, the more precisely; often require fresh material |
| For worm eggs (helminths) | 4-5 hours | Up to 8-10 hours | Parasitic eggs are more resistant to cold |
| For carbohydrates | No more than 2 hours | Not recommended | Exclusively fresh, warm material is required |
As can be seen from the data, the most demanding is the analysis for dysbacteriosis. For him anaerobic bacteria, which die upon contact with oxygen, must be delivered to the laboratory almost instantly. In some cases, clinics do not even accept such material that has been in the refrigerator for more than three hours, since the ratio of beneficial and harmful flora has time to change.
For coprograms, the requirements are softer. If the child went to the toilet at 20:00, and you plan to take the test at 8:00 in the morning, storing it in the refrigerator is acceptable. However the ideal option is always to deliver the material within 2 hours after defecationwhich guarantees maximum diagnostic accuracy.
⚠️ Attention: If the doctor’s direction indicates “fresh feces” or “warm”, storage in the refrigerator is prohibited. In such cases, the material must be delivered to the laboratory within 40-60 minutes.
Rules for collecting stool from children of different ages
Collection technique biomaterial differs significantly depending on the age of the child and his skills in controlling physiological processes. For infants who are not yet sitting on their own, using a regular potty is impossible, since there is a high risk of mixing feces with urine or water if the potty has been previously washed.
The optimal solution for infants is to use sterile urinal (for loose stools) or clean plastic film stretched under the butt. Diapers and nappies cannot be used: they instantly absorb the liquid fraction, leaving only dense lumps on the surface, which distorts the analysis result.
For children over one year old who already use a potty, the task is simplified. The pot must be thoroughly washed with soap, doused with boiling water and dried. The use of chemical disinfectants (chlorine, chlorine-containing detergents) is unacceptable, since their residues may react with the biomaterial.
- 👶 For newborns: use sterile film or a special bag-overlay for the potty.
- 🧸 For toddlers (1-3 years): a clean, dry potty without traces of detergents funds.
- 🚽 For older children: you can use a special shovel to remove from the toilet if a highchair is installed.
It is important to take material from different places in the fecal mass: top, bottom and middle. This will allow you to obtain a representative sample, especially if there is mucus or streaks of blood in the stool - they need to be captured first.
Technology for proper packaging and transportation
After collecting the material, it must be immediately placed in a sterile container. These containers are sold in pharmacies and are inexpensive, but their value in preserving the quality of the sample is enormous. They are made of chemically inert plastic that does not react with the components of feces.
The container should be filled no more than one third. The remaining space is necessary to ensure that when opening the lid in the laboratory, the material does not leak out and stain the hands of personnel. The lid must be screwed tightly, until a characteristic click is heard, ensuring complete tightness.
When transporting in the cold season, it is better to place the container in a clothing pocket, closer to the body, so that it does not get too cold below the permissible values, but also does not heat up excessively from the heat of the hands. If you are transporting material in the summer, be sure to use cold packs, but make sure that the container does not touch them directly to avoid local freezing.
⚠️ Attention: Do not sign the container lid with a marker if the paint may dissolve due to condensation. It is better to stick a label with patient data on the side of the glass or use a special referral form.
☑️ Proper packaging of the sample
Typical mistakes of parents when storing
One of the most common mistakes is storing open container. Some parents believe that simply placing the glass on the refrigerator shelf is enough. This is a serious violation: the open surface is quickly contaminated with foreign bacteria from the air of the refrigeration chamber, and also loses moisture.
Another common mistake is the use of household containers (matchboxes, baby food jars, plastic glasses). Even a thoroughly washed puree jar is not sterile and may contain traces of fats or proteins that will interfere with the chemical analysis. In addition, the walls of such containers may be porous and contain microscopic remains of the previous contents.
Some parents try to “refresh” the material by adding water or saline solution if the stool is dry or there is little of it. This is absolutely not allowed! This completely changes the concentration of substances and makes the analysis meaningless. If there is not enough material, donate as much as you have, but do not dilute it.
The myth about the freezer
There is a strong opinion that feces can be frozen “in reserve.” This misconception is dangerous because after defrosting, the cell structure is destroyed, and the laboratory technician will not be able to detect either protozoa or leukocytes.
Frequently asked questions and additional recommendations
Parents often ask whether it is possible to collect feces in the evening if the child goes to the toilet only at night. Yes, this is acceptable for coprogram and test for worm eggs, but the container must be tightly closed and placed in the refrigerator immediately after cooling to room temperature.
It is also important to remember about the diet. If the doctor has prescribed a test for occult blood, 3 days before the test you need to exclude meat, fish, tomatoes and green vegetables from your diet, as they can give a false positive result. For analysis of carbohydrates (lactase deficiency), the diet, on the contrary, should be normal in order to show the real picture of milk absorption.
If you notice strange inclusions, mucus or blood in the stool, be sure to take a photo before collection or indicate this in the direction. For a laboratory technician, this can be an important clue as to where exactly to look first during microscopy.
Is it possible to store feces in the refrigerator for more than 12 hours?
No, storing biomaterial for more than 12 hours (even for coprograms) is not recommended. During this time, even at low temperatures, irreversible changes occur in the composition of bacteria and enzymes. The result of such an analysis will be unreliable, and the doctor may prescribe the wrong treatment.
What to do if a child pooped in a diaper?
Collecting feces from a disposable diaper is extremely difficult, since it absorbs liquid. If there is no other option, try carefully scraping off only the surface layer using a sterile spoon, avoiding getting the absorbent gel from inside the diaper. However, it is better to place a clean film under the child next time.
Do you need to warm up the feces before donating?
No, you cannot warm up the material. If it was stored in the refrigerator, you can simply hold it in your hands for 5-10 minutes to warm it to room temperature. Artificial heating (battery, microwave) will kill beneficial flora and destroy the structure of the sample.
Does taking antibiotics affect the result?
Yes, antibiotics significantly change the intestinal microflora. If the purpose of the analysis is to check for dysbiosis, then it must be taken either before starting to take the drugs, or 10-14 days after finishing the course, otherwise the result will simply show the effect of the medicine, and not the real state of health.