A false positive in the cancer screening kit means that, although there is no actual malignant tumor, the test results indicate a high likelihood of cancer (in the 4-5 range). Conditions such as pyometra, pancreatitis, immune-mediated hemolytic anemia, and other infections, inflammation, or autoimmune diseases that can elevate CRP levels may lead to a false positive result. If such underlying conditions are identified, it is recommended to wait until the symptoms are fully resolved and then perform a retest 2-4 weeks later.
A false negative in cancer screening kits refers to a situation where a malignant tumor is present, but the test result shows a cancer risk in the 1-3 range. In such cases, the following factors should be considered:
As individuals age, factors like chronic inflammation, aging, and stress can cause cells to fail to divide normally or suffer genetic damage. In most cases, these abnormal cells are eliminated by the immune system, but some may proliferate into malignant tumor cells. During this process, mutated cells secrete substances associated with malignant tumors. If these abnormal cells are removed by the immune system, these substances may temporarily increase and then return to normal levels.
A tumor biomarker test refers to the examination of substances produced by tumors or in response to tumors in the body. These tests are valuable for cancer screening, diagnosis, prognosis assessment, and evaluating treatment efficacy.
Generally, it is important to observe not only the level of the tumor biomarker but also how it changes over time. For patients with elevated tumor biomarkers without any specific cause or symptoms, it is recommended to perform follow-up tests at appropriate intervals. If the levels remain the same or decrease after follow-up testing, the likelihood of a malignant tumor is low. In such cases, monitoring may be stopped, or treatment for a treatable benign condition may be recommended. However, if the levels increase by 10-25% or more, further testing (such as ultrasound or CT scans) is recommended to rule out potential malignant diseases, and the tumor markers should continue to be monitored. (Sölétormos G, Schiøler V, Nielsen D, Skovsgaard T, Dombernowsky P. Interpretation of results for tumor markers on the basis of analytical imprecision and biological variation. Clin Chem. 1993 Oct;39)
Precancerous stages refer to dysplastic tissues made up of abnormally dividing cells, which are not yet considered cancerous but have the potential to progress into malignant tumors in the future. Micro cancer refers to cancerous tissue that has already progressed but cannot be detected by imaging tests like ultrasound or CT scans. This stage occurs before the primary tumor has grown beyond a certain size or before metastatic cancer is diagnosed.
In both precancerous stages and micro cancer, tumor marker tests may show elevated levels, so repeated follow-up tests are crucial for early detection of cancer, which plays a key role in treatment and prognosis.
Immune evasion refers to the ability of cancer cells to escape the immune surveillance system through various mechanisms. Several hypotheses have been proposed regarding the mechanisms of immune evasion, but it is generally understood to occur through the process of immune editing—elimination—equilibrium—escape. The elimination phase is when the immune system recognizes and effectively removes tumor cells, while during the equilibrium phase, the immune system can no longer remove tumor cells, but can suppress their growth. In the escape phase, the immune system's ability to eliminate or control the tumor is overwhelmed, leading to tumor growth and metastasis. This process occurs as tumor cells acquire the ability to suppress or evade the immune system.
When antigen expression exceeds a certain threshold and continuously stimulates the immune system, the immune system may no longer recognize the antigens produced by the cancer as abnormal proteins. This phenomenon causes a reduction in the number of autoantibodies produced by B cells compared to the early stages of cancer. Additionally, some cancer cells may not present protein antigens on their surface, preventing antigen-presenting cells from recognizing them as harmful, thus no autoantibodies are produced. These cancer cells essentially become "invisible." Some cancer cells can block certain steps of the immune process that would normally identify and destroy them. For example, by inhibiting the function of the NLRC5 gene, these cells protect themselves from being destroyed by cytotoxic T cells. In this way, cancer cells evade the body's immune surveillance system to survive. Many researchers are still studying immune evasion and, based on this, are looking for methods to detect, treat, and monitor cancer cells.
Cancer screening kits cannot distinguish these immune evasion mechanisms in cancer cells. As a result, false negatives may occur in some malignant tumors, and caution is needed when interpreting the results.
The cancer screening kit results are indicated in ranges of 1-5 or 0-99%. If the result falls within the 1-3 range (55% or less), the likelihood of malignant tumors developing in the future is low. On the other hand, if the result falls within the 4-5 range (above 55%), the likelihood of malignant tumors developing is high. This also means that even if no visible malignant tumors are currently detected, the body is in a state that is prone to cancer, so changes in diet and environment, along with regular monitoring, are necessary. However, since the body's condition is constantly changing, periodic tests every 3-12 months are recommended depending on the patient's age and health status. It is advisable to consult with the attending veterinarian regarding the testing schedule.
The cancer screening kit test result was in the low range (1-3 range, 55% or less), and if there are no other abnormalities during the health check-up, the likelihood of malignant tumor development is low. However, no test is 100% accurate, and there is a possibility of false negatives. Since the body's condition can change over time, it is recommended to monitor appetite, vitality, and other factors while performing the cancer screening kit test during health check-ups every 6 to 12 months.
A result in the 4-5 range (above 55%) in a cancer screening kit test does not necessarily mean that a malignant tumor is present or will develop. However, it is necessary to confirm whether a malignant tumor exists by conducting other health screenings. Even if no evidence of a malignant tumor is found during the health check-up, there is still a possibility that the tumor could be in a pre-cancerous or micro-cancer stage. Therefore, it is important to monitor appetite, vitality, and the presence of any visible lumps, with regular follow-up every 2-4 months.
The cancer screening kit test provides the final report based on an artificial intelligence model that analyzes six factors: PKA, CRP, IgG, and the patient's gender, age, and breed. While PKA levels are significantly elevated in malignant tumors, a single tumor marker has low sensitivity and specificity. Therefore, the final result from the AI model is much more accurate. However, due to interference from other factors or because the tumor is in an early stage, PKA values may be high while the final result is in the low range. If the PKA value is excessively high, it is recommended to consult with the attending veterinarian and adjust the testing interval to 2-4 months for follow-up tests.
The immune system is responsible for eliminating mutated cells that may lead to cancer. Therefore, in elderly patients with reduced immune function, the likelihood of malignant tumors increases. Conversely, immune suppression can also be caused by malignant tumors. Therefore, while there may be no current evidence of a malignant tumor, if the IgG level is low and the cancer probability result is high (4-5 range, 55% or higher), it indicates a higher risk of developing a malignant tumor. It is important to be cautious in this case. Administering supplements such as antioxidants, liver protectants, and immune boosters, as well as creating an environment to reduce stress, should be considered. Follow-up tests should be conducted to track whether IgG levels improve.
Many research studies have shown that CRP levels significantly increase in patients with malignant tumors. Therefore, the cancer screening kit also measures CRP levels. However, in cases of infections, inflammation, or autoimmune diseases, such as pyometra, pancreatitis, or immune-mediated hemolytic anemia, CRP levels can also rise, which may lead to false positives. If such underlying conditions are identified, it is recommended to perform a re-test 2-4 weeks after the symptoms have completely resolved. If the cancer screening kit shows a high result due to CRP, it is expected that the levels will return to a lower range once the underlying condition has fully recovered.
When a malignant tumor is diagnosed, but the screening test results indicate a low cancer probability range (1-3 range, within 55%), this is referred to as a false negative. Several factors should be considered in such cases:
Possible pathological causes that can decrease immunoglobulin levels include long-term use of immunosuppressive drugs, nutritional deficiencies due to digestive symptoms such as anorexia and vomiting (which affect protein digestion, absorption, or leakage through the intestines or kidneys), liver dysfunction, and malignant tumors. If immunoglobulin levels remain low despite repeated testing and supplementation with immune enhancers, antioxidants, and other supplements, further investigation into underlying conditions is necessary.
Pathological causes that can increase immunoglobulin levels include infections caused by bacteria or viruses, autoimmune diseases such as chronic stomatitis and atopic dermatitis, which are associated with heightened immune activity. If high levels persist in repeated tests, additional testing is needed to investigate underlying conditions.
Glycosylated hemoglobin (HbA1c) is a complex formed when hemoglobin in red blood cells binds with glucose in the blood, and it can provide an estimate of blood glucose levels over the past 1-2 months. For patients whose blood glucose is well-maintained and who visit the clinic every 2-3 months, the HbA1c test, which has a longer half-life than fructosamine, may be more useful. However, the frequency of testing can vary depending on the patient's condition, so it is recommended to consult with the attending veterinarian for the appropriate HbA1c testing schedule.
In humans, glycosylated hemoglobin levels are measured during routine health check-ups to differentiate prediabetes and to recommend dietary changes and weight management to prevent further progression. In dogs, diabetes is generally classified as Type 1, but conditions such as hyperadrenocorticism, repeated steroid use, and chronic pancreatitis are known to accelerate the progression to diabetes. Therefore, for patients with these underlying conditions, periodic measurement of glycosylated hemoglobin levels to check for prediabetes is recommended. If prediabetes is suspected, special attention to diet and weight management may be required.
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If the sample volume is insufficient or if the kit's expiration date/storage conditions have not been properly checked, this could affect the results. If the test was conducted properly, consider the following factors: patients on long-term steroid treatment, those with poorly managed hyperadrenocorticism, or patients who have undergone splenectomy may have prolonged red blood cell lifespan, which can lead to higher results.
The HbA1c test is influenced by red blood cell volume. In patients who have experienced complications such as diabetic ketoacidosis (DKA) or those who have developed non-regenerative anemia due to inflammation or infection, the red blood cell volume may decrease. This reduction leads to fewer red blood cells binding to glucose, which can result in a normal HbA1c test result. In such cases, it is recommended to repeat the test after the complications are resolved and anemia has been treated.
CRP is a protein that is rapidly produced in the body in response to infections, inflammation, and other stimuli. Even if symptoms such as fever, fatigue, or loss of appetite are not present, CRP levels can increase if there is hidden inflammation or infection somewhere in the body. For dogs, who cannot directly express where they feel pain like humans, testing for CRP during a health check-up can help detect hidden inflammation or infections early, which is crucial for effective treatment.
In dogs over the age of 7, age-related changes such as nodular hyperplasia (regenerative nodules) and hepatic cysts are common in the liver. These lesions are often detected via ultrasound and typically do not cause significant problems. If abnormal changes are found in the liver during a health check-up but the AFP test result is normal, these are likely benign lesions. However, in the case of slowly growing hepatocellular carcinoma, the AFP levels may still be close to normal, so regular monitoring of the mass size is recommended.
AFP levels generally increase only in patients with malignant tumors, so they are not typically elevated in other liver diseases. However, if a malignant tumor is not visibly detectable, AFP levels may rise without being identified on imaging tests. In such cases, it is important to monitor the patient while treating the underlying liver condition and follow up with additional tests.
In cases of malignant liver tumors like hepatocellular carcinoma, hemangiosarcoma, and spindle cell sarcoma, AFP levels are typically more than 100 times higher than normal. However, in certain slowly growing tumors such as hepatocellular carcinoma with biologically benign characteristics, the increase in AFP may be minimal. Additionally, in patients with severe liver dysfunction, where protein production is impaired, AFP levels may not rise significantly.
Canine parvovirus (CPV) is a highly contagious virus with strong resistance to environmental conditions, and it spreads from dog to dog through direct or indirect contact with feces, saliva, etc. If sufficient antibodies have been developed through vaccination, infection can be prevented. However, the mortality rate is extremely high (over 50%) in infected young dogs. After infection, symptoms such as lethargy, vomiting, fever, and diarrhea appear within 2-14 days. The rapidly dividing parvo virus proliferates in the intestinal epithelium, causing damage to the intestinal mucosa, leading to dehydration and electrolyte imbalance, and eventually causing death due to secondary bacterial infections and endotoxemia. Severe leukopenia is often observed. There is no clear treatment, but symptomatic treatments, such as correcting dehydration and preventing secondary infections, can be attempted. Antiserum may be helpful.
Canine distemper virus (CDV) is a respiratory virus that infects all canid species, including dogs. It is highly contagious and transmitted through respiratory droplets, with a mortality rate reaching 50%. Symptoms typically appear 2-3 days after infection and include high fever, conjunctivitis, eye/nasal discharge, labored breathing, coughing, vomiting, diarrhea, and lethargy. Even after recovery, sequelae such as hyperkeratosis of the nose and paws, dental enamel hypoplasia, and neurological symptoms may occur. There is no definitive treatment, and symptomatic care is provided.
Canine adenovirus (CAV) causes infectious hepatitis in dogs. Although it is now rare in Korea, it is a highly contagious disease that can be transmitted through direct contact or by coming into contact with contaminated environments or objects. The incubation period is 6-9 days, but infected dogs can shed the virus in their urine for up to 9 months, so caution is necessary. Symptoms typically include high fever and multiple vasculitis, and in severe cases, chronic kidney lesions, corneal opacity (blue eye), and neurological symptoms may occur. The mortality rate is relatively low, around 10-20%. There is no specific treatment, and symptomatic care is provided.
Canine coronavirus (CcoV) is a highly contagious viral infection that causes gastrointestinal disease. Similar to parvovirus, it invades the small intestine villi and multiplies, but unlike parvovirus, it does not cause severe intestinal damage. As a result, most dogs are asymptomatic, or it causes mild diarrhea in puppies. The incubation period is 1-3 days, but the virus can be detected in the feces of infected dogs for up to 6 months. Symptoms include diarrhea, vomiting, and lethargy. The condition generally improves with symptomatic treatment. However, when puppies are co-infected with parvovirus, the mortality rate can be very high.
Kennel cough (Kennel Cough, KC), a general term for infectious bronchitis or respiratory diseases in dogs, is primarily caused by Bordetella bronchiseptica. The infection rate is high, but the mortality rate is low. It typically causes symptoms such as sneezing, coughing, and nasal discharge, and most dogs recover naturally. However, in puppies or elderly dogs, co-infection with other respiratory viruses can lead to worsened symptoms or progression to pneumonia, requiring caution.
Canine influenza virus (CI) is an influenza virus that affects canids and is a highly contagious respiratory infection. The infection rate is generally high, but the mortality rate is low, with coughing and nasal discharge being the main symptoms. In severe cases, pneumonia or secondary infections may develop, so caution is needed. While it can naturally resolve without specific treatment, it is important to monitor puppies or elderly dogs with underlying conditions to ensure it does not progress to pneumonia or other complications.
Puppies receive maternal-derived antibodies (MDA) in the womb and through breast milk. These antibodies gradually diminish between 8 to 12 weeks of age. If maternal antibodies are still present in high levels, they can interfere with the vaccine's effectiveness, leading to poor antibody production. Additionally, puppies' immune systems are not fully mature, so even after five rounds of basic vaccinations, they may not generate sufficient antibody levels. The immune system typically matures around the first year of life. In rare cases, there may be vaccine non-responders, which are individuals whose immune systems fail to produce adequate antibodies due to immune system abnormalities, making them more susceptible to infectious diseases. In such cases, careful management of their daily care is essential.
If proper basic vaccinations were administered during their early stages, adult dogs should retain sufficient levels of antibodies. However, since the degree of immune system maturity and antibody production can vary between individual dogs, some infectious diseases may require periodic booster vaccinations to replenish decreasing antibody levels. For this reason, it is recommended to perform antibody tests during routine health check-ups. Depending on the antibody levels, additional vaccinations can be determined, helping to prevent over-vaccination.
As dogs age, their immune system weakens, and if they haven't received booster vaccinations over a long period, the antibodies they previously had may decrease. Additionally, senior dogs may already have one or more metabolic diseases, and if their body functions are impaired, they may be more vulnerable to infectious diseases. In South Korea, where winters are long, and especially since parvovirus can remain infectious in outdoor environments for over six months, senior dogs that stay indoors could still be exposed to infectious diseases through interactions with other dogs during walks, visits to the vet, or contact with their owners.
By conducting antibody tests during health check-ups, the levels of antibodies can be easily assessed, helping to determine whether additional vaccinations are needed.