Taking stool tests in children is a procedure that requires not only the correct collection of material, but also its proper storage before delivery to the laboratory. Many parents are faced with the question: Is it possible to store a child’s feces in the refrigerator, and if so, how many hours or days does it remain suitable for research. Errors at this stage can distort the results, which will lead to incorrect diagnosis or repeated tests.
In this article we will analyze permissible periods for storing feces in the refrigerator for different types of tests (coprogram, worm eggs, dysbacteriosis, calprotectin test), suitable temperature conditions, as well which containers are best to useto preserve the biomaterial in its original condition. We will separately dwell on the typical mistakes that parents make and explain why some storage methods (for example, in the freezer or at room temperature) are absolutely not suitable.
It is worth considering that the requirements of laboratories may differ - for most standard tests, a child’s stool can be stored in the refrigerator for no more than 8–12 hours at a temperature of +2...+8°C, but there are studies where this period is reduced to 2-4 hours. Below you will find detailed recommendations for each type of analysis, as well as tips on how to avoid spoilage of the material.
Why is it important to observe the shelf life of stool
Stool is a biologically active medium in which after During bowel movements, enzymatic processes continue to occur, bacteria multiply and cells disintegrate. If the material is stored for too long or at the wrong temperature, its composition changes:
- 🔬 Changes in microflora: pathogenic and opportunistic bacteria can multiply or, conversely, die, which will distort the results of the analysis for dysbacteriosis.
- 🧬 Decomposition of enzymes and proteins: at room temperature enzymes (for example, lipase, amylase) quickly lose activity, which will affect the coprogram.
- 🐛 Death of parasites: worm eggs and protozoan cysts (giardia, amoebas) can be deformed or destroyed during freezing or long-term storage.
- 📉 Changes in pH and consistency: stool dries out or, conversely, becomes watery, which makes microscopic examination difficult.
Laboratories often refuse to accept material that has been stored longer than the permissible period, since its diagnostic value is reduced. For example, for calprotectin analysis (marker of intestinal inflammation) it is critical to maintain a temperature of +2...+4°C and a period of no more than 5 days, otherwise the protein will denature and the test will show a false negative result.
Permissible periods for storing stool in the refrigerator for different tests
The shelf life of biomaterial depends on the type of study. Below is a table with recommendations for the most common tests in children. All data is relevant for storage in an airtight container at a temperature of +2...+8°C (the main shelf of the refrigerator, not the door!).
| Type of analysis | Maximum shelf life | Notes |
|---|---|---|
| Coprogram (general stool analysis) | 8–12 hours | If stored for more than 6 hours, changes in consistency and enzymatic activity are possible. |
| Analysis for worm eggs and protozoa | up to 24 hours | Giardia cysts are preserved better than roundworm eggs. For accuracy, it is better to take it within 4–6 hours. |
| Analysis for dysbacteriosis | 2–4 hours | The microflora changes quickly. Some laboratories take samples up to 6 hours when using a preservative. |
| Analysis for calprotectin | up to 5 days | Only in special tubes with a preservative (for example, Calprotectin Extractor). Without preservative - no more than 24 hours. |
| Hidden blood test | no more than 6 hours | Hemoglobin is destroyed during long-term storage, false negative results are possible. |
Please note: for analysis of dysbacteriosis many laboratories require delivery of stool within 2 hours after collection. This is due to the fact that anaerobic bacteria (for example, bifidobacteria) die when exposed to oxygen. If you do not have time to deliver the material so quickly, use special transport Wednesday (for example, Port-a-Cul or Copan UTM), which are sold in pharmacies or issued in laboratories.
At what temperature to store the child's stool
The optimal temperature for storing stool before analysis is +2…+8°C. This is the range in which biochemical processes slow down, but there is no death of microorganisms or denaturation of proteins. It is important to understand that:
- ❄️ Storage in the freezer (−18°C and below) is strictly prohibited for most analyzes (except for special studies, where this is stipulated by the laboratory). Freezing destroys cells, parasite eggs and enzymes.
- 🌡️ Room temperature (+18...+25°C) accelerates the proliferation of bacteria and the breakdown of stool components. It is permissible only if the material is delivered to the laboratory within 1–2 hours.
- 🧊 Refrigerator door is not the best place for storage, since the temperature there fluctuates when opened. Use the main shelf.
For some tests (for example, for calprotectin or DNA of parasites), storage at −20°C is allowed, but only if this is specifically stated in the laboratory instructions. In such cases, the material is frozen once and thawed immediately before delivery.
⚠️ Attention: If your refrigerator has a zone Fresh Zone (0...+1°C), it can be used for storing feces, but not longer than 6 hours. A longer stay at this temperature can lead to condensation of moisture and liquefaction of the sample.
How to properly collect and store child’s feces: step-by-step instructions
For the analysis results to be reliable, it is important not only to observe the storage period, but also to collect the material correctly. Below are detailed instructions for parents.
Wash the child with warm water without soap 1-2 hours before bowel movement|
Use a clean potty or vessel (for infants - a diaper, but not a diaper)|
Collect the stool in a sterile container with spoon (at least 1–2 g for coprogram, 5–10 g for analysis for worm eggs)|
Close the container tightly and sign it (full name, date, time of collection)|
Place the container in the refrigerator on the main shelf (not in the door!)-->
Additional recommendations:
- 👶 For infants: if the child cannot poop in the potty, use a urine collector with an adhesive baseattaching it to the baby's bottom. This will help prevent urine from getting into the stool.
- 💊 3 days before collecting stool, avoid taking it antibiotics, laxatives, sorbents (unless agreed with your doctor). Also, do not introduce new complementary foods.
- 🩸 If the test is for occult blood, exclude meat, fish, tomatoes, cucumbers and green vegetables from the child’s diet for 2-3 days.
If a child suffers from constipation, do not use an enema or glycerin suppositories without the consent of the pediatrician - this may distort the results. It is better to collect stool the next day after natural bowel movement.
What to do if the child cannot poop in the morning?
If the laboratory accepts tests only in the morning, and the child went to the toilet in the evening, collect the stool in a sterile container and store it in the refrigerator at +2...+8°C. The main thing is to meet the acceptable deadlines for your type of analysis (see table above). If the storage period has expired, it is better to reschedule the visit to the laboratory the next day.
What containers are suitable for storing feces
Not every container is suitable for storing feces. Optimal options:
- 🧪 Sterile plastic containers with a spoon and a tight lid (sold in pharmacies). They are sealed and do not react with biomaterial.
- 🧊 Containers with a preservative (for example, for analysis of calprotectin or dysbacteriosis). Such containers are given out in laboratories or sold in specialized medical stores.
- 🥛 Glass jars (from baby puree) - only as a last resort! Pre-sterilize them with boiling water and dry them. The lid must close tightly.
What to do You cannot:
- 🚫 Use matchboxes, plastic bags or foil - they are not airtight and can absorb moisture.
- 🚫 Storing feces in a diaper or cotton swab - this contaminates the material with fibers and chemicals.
- 🚫 Transferring feces from one container to another before donation - this increases the risk of foreign microorganisms.
If you use a container with preservative, make sure that the stool is completely immersed in liquid. This will prevent oxidation and preserve microflora. For example, for analysis of rotavirus infection a preservative is often used, which stabilizes the RNA of the virus. Alcor Bio, which stabilizes the RNA of the virus.
⚠️ Attention: Some laboratories refuse to accept feces in uncertified containers (for example, in baby food jars). Specify the requirements in advance so that you do not have to retake the test.
Typical mistakes of parents when storing feces
Even experienced parents sometimes make mistakes that lead to inaccurate test results. Here are the most common:
- Storing feces in the freezer without specifying the laboratory. Freezing kills parasites and destroys cells, making analysis for worm eggs or coprogram uninformative.
- Use of non-sterile containers, for example, mayonnaise jars. Residues of fat or detergents distort the results.
- Long-term storage at room temperature. Within 2–3 hours, bacteria begin to multiply in the feces, which is especially critical for analysis of dysbiosis.
- Collecting feces after an enema or laxatives. This changes the consistency and composition of the microflora, which leads to false results.
- Unsigned container. Without indicating the full name, date and time of collection, the laboratory may refuse to accept the material.
Another common mistake is collecting feces from the diaper. The absorbent layer of the diaper contains gelling agents that mix with the stool and make it unsuitable for analysis. If the child pooped in the diaper, carefully collect the top layer (without touching the absorbent material) with a clean spoon.
What to do if the shelf life has expired
If you did not manage to deliver the stool to the laboratory within the acceptable time frame, you have several options:
- 📞 Call the laboratory and find out whether they accept material with an expired shelf life. Some clinics make exceptions for tests for worm eggs (if the stool was stored for no more than 36 hours).
- 🔄 Collect a new sample. This is the most reliable method, especially for tests for dysbacteriosis or calprotectin.
- ❄️ Freeze stool (only if this is allowed for your type of analysis!). For example, for PCR diagnostics of parasites, a single freeze at −20°C is sometimes allowed.
If you decide to donate “stitched” stool, be sure to notify the laboratory assistant about this. On the referral form, indicate the actual collection time and storage conditions. This will help specialists correctly interpret the results.
In some cases, the laboratory may offer rapid teststhat are less sensitive to shelf life. For example, to detect H. pylori or rotavirus, test strips are sometimes used that work even with “old” material.
⚠️ Attention: If feces were stored longer than the permissible period, but did not change in appearance (did not dry, did not change color), this does not mean that it is suitable for analysis. Biochemical changes may be invisible to the eye, but will distort the results.
FAQ: Frequently asked questions about storing baby feces
Is it possible to store baby feces in the refrigerator on the door?
No, the refrigerator door is - not the best place to store feces. The temperature there is less stable due to frequent opening, which can lead to overheating or freezing of the sample. Use the main shelf, where the temperature is kept in the range of +2...+8°C.
How long can you store stool for analysis for dysbacteriosis?
For analysis for dysbacteriosis, it is advisable to deliver the child’s stool to the laboratory within 2-4 hours. The maximum shelf life in the refrigerator is 6 hours, but only in a sterile container with a preservative (if provided by the laboratory). Without a preservative, the microflora changes quickly, and the results will be unreliable.
Is it possible to freeze feces for analysis for worm eggs?
No, freezing destroys parasite eggs and protozoan cysts. To test for worm eggs, feces should be stored at +2...+8°C for no more than 24 hours. If you do not have time to take the test within this period, collect a new sample.
What happens if the feces were stored in the refrigerator longer than the permissible period?
The consequences depend on the type of analysis:
- For coprograms: the indicators of enzymes, mucus, leukocytes.
- For analysis for dysbacteriosis: the ratio of bacteria will be distorted.
- For test for worm eggs: parasites may die, and the test will show a false negative result.
The laboratory may refuse to accept such material or will give a result marked “conditionally reliable.”
Can a baby puree container be used to store feces?
As a last resort - yes, but only if the jar is glass, with a tight lid, and you have previously sterilized it with boiling water. Plastic puree containers are not suitable as they may react with stool components. It is better to buy a special sterile container at the pharmacy.