Can test results be wrong? Can test results be wrong? List of drugs that can affect the level of hCG

Can a hepatitis C test be wrong? Unfortunately, such cases sometimes happen. This pathology is dangerous because after infection, symptoms are often absent in a person for many years. Accuracy in the diagnosis of hepatitis C is especially important, since if it is not detected and treated in time, the disease leads to catastrophic complications: cirrhosis or liver cancer.

Types of diagnostics

Hepatitis C viruses are transmitted through the blood, so its analysis is important. The immune system produces protein antibodies against pathogens - immunoglobulins M and G. They are markers by which a liver infection is diagnosed using enzyme-linked immunosorbent assay (ELISA).

About a month after infection or during an exacerbation of chronic hepatitis C, class M antibodies are formed. The presence of such immunoglobulins proves that the body is infected with viruses and rapidly destroys them. During the patient's recovery, the number of these proteins is steadily declining.

Antibodies G (anti-HCV IgG) are formed much later, in the period from 3 months to six months after the invasion of viruses. Their detection in the bloodstream indicates that the infection happened a long time ago, so the severity of the disease has passed. If there are few such antibodies and in the re-analysis it becomes even smaller, this indicates the recovery of the patient. But in patients with chronic hepatitis C, immunoglobulins G are always present in the circulatory system.

In laboratory tests, the presence of antibodies to non-structural viral proteins NS3, NS4 and NS5 is also determined. Anti-NS3 and Anti-NS5 are detected early in the disease. The higher their score, the more likely it is to become chronic. Anti-NS4 helps determine how long the body has been infected and how severely the liver is affected.

A healthy person has no blood tests. Each of these liver enzymes indicates an early stage of acute hepatitis. If both are found, then this may signal the onset of liver cell necrosis. And the presence of the GGT enzyme (gamma-glutamyl transpeptidase) is one of the signs of organ cirrhosis. Evidence of the destructive work of viruses is the presence in the blood of bilirubin, the enzyme alkaline phosphatase (alkaline phosphatase), and protein fractions.

The most accurate diagnosis, if carried out correctly, is by PCR (polymerase chain reaction). It is based on the detection of not immune antibodies, but the structure of RNA (ribonucleic acid) and the genotype of the causative agent of hepatitis C. 2 variants of this method are used:

• qualitative - is there a virus or not;
• quantitative - what is its concentration in the blood ().

Deciphering the results

"Hepatitis C test is negative." This formulation confirms the absence of the disease in a qualitative study by PCR. A similar result of a quantitative ELISA test shows that there are no virus antigens in the blood. In immunological studies, their concentration is sometimes indicated below the norm - this is also a negative result. But if there are no antigens, but there are antibodies to them, this conclusion signals that the patient has either already had hepatitis C or has recently been vaccinated.

"Hepatitis C test positive." This wording needs clarification. A laboratory can give a positive result to a person who once had it in an acute form. The same wording applies to people who are currently healthy but are carriers of the virus. Finally, it may be a false analysis.

In any case, it is necessary to conduct a study again. For a patient with acute hepatitis C who is on treatment, the doctor may prescribe testing every 3 days to monitor the effectiveness of therapy and the dynamics of the condition. A patient with a chronic illness should take control tests every six months.

If the result of the antibody test is positive and the conclusion of the PCR test is negative, the person is considered to be potentially infected. To verify the presence or absence of antibodies, diagnostics are carried out using the RIBA method (RIBA - recombinant immunoblot). This method is informative 3-4 weeks after infection.

Options for false analyzes

In medical practice, there are 3 options for inadequate results of a diagnostic study:

• doubtful;
• false positive;
• false negative.

The enzyme immunoassay method is considered very accurate, but sometimes it gives erroneous information. Doubtful analysis - when the patient has clinical symptoms of hepatitis C, but there are no markers in the blood. Most often this happens when the diagnosis is too early, because the antibodies do not have time to form. In this case, a second analysis is done after 1 month, and a control one after six months.

The doctor receives it when class M immunoglobulins are detected by the ELISA method, and the virus RNA is not detected by the PCR method. Such results are often found in pregnant women, patients with other types of infection, and cancer patients. They also need to be retested.

False-negative results appear very rarely, for example, in the incubation period of the disease, when a person is already infected with the hepatitis C virus, but is also immune to it and symptoms are still absent. Such results can be in patients who take drugs that suppress the body's defense system.

What else is determined in the diagnosis?

Hepatitis C progresses differently depending on the genotype of the virus. Therefore, during the diagnosis, it is important to determine which of the 11 variants is in the patient's blood. Each genotype has several varieties, which are assigned letter designations, for example, 1a, 2c, etc. You can accurately select the dosage of drugs, the duration of treatment, by recognizing the type of virus.

In Russia, genotypes 1, 2 and 3 are predominantly common. Of these, genotype 1 is treated the worst and the longest, especially subtype 1c. Variants 2 and 3 have more favorable forecasts. But genotype 3 can lead to a severe complication: steatosis (fatty liver). It happens that a patient is infected with viruses of several genotypes at once. At the same time, one of them always dominates over the others.

Diagnosis of hepatitis C is indicated if:

Causes of erroneous analyzes

False positive tests, when there is no infection in the body, but the results indicate its presence, make up to 15% of laboratory tests.

Causes of errors:

False positive test results are possible if the expectant mother:

• metabolism is disturbed;
• there are endocrine, autoimmune diseases, flu and even a common cold;
• specific pregnancy proteins appear;
• the level of trace elements in the bloodstream decreases sharply.

In addition, when testing for hepatitis C, the causes of errors may lie in the human factor. Often affected:

• low qualification of the laboratory assistant;
• erroneous analysis of someone else's blood;
• low-quality chemicals;
• outdated medical devices;
• contamination of blood samples;
• violation of the rules of their transportation and storage.

Any laboratory can make mistakes sometimes. But this is possible with only ELISA tests or only PCR. Therefore, when diagnosing a disease, both research methods should be used. Then it is most reliable, since it is difficult to make a mistake if there is no virus in the blood.

It is important to test for hepatitis C when there are no ailments, even a mild cold. It is not required to donate blood on an empty stomach. You should only give up fatty, fried, spicy foods the day before, do not drink alcohol. One last thing: an initial false-positive result for hepatitis C is not a reason to panic. The conclusion should be made only after additional research.

External manifestations that appear in the later stages are easily confused with other diseases. Therefore, a lot depends on the results of laboratory tests. But even this branch of medicine cannot yet offer a universal analysis for the verification of syphilis.

Syphilis Tests: Diagnostic Approaches

All methods that are used to detect syphilis fall into two different categories.

The key difference between them is this:

• Search directly for the pathogen. These are the so-called direct tests. The material is a fragment of tissue obtained from a suspicious focus.
• A study to identify specific antibodies - immunoglobulins - that the immune system produces in response to the entry of pale treponema into the blood. The material for research is blood plasma.

Both of these categories have their own advantages and disadvantages. In the first case, it is important that the spirochete cells get into the test sample (high specificity, but not always acceptable sensitivity).

Methods from the second category, on the contrary, have high sensitivity, but their specificity leaves much to be desired. So the true answer to the question, can a syphilis test be wrong, unequivocally: yes. And in both directions - or false negative. Especially if the study was conducted using only one method.

Syphilis analysis: direct tests

This includes tests for syphilis, which can detect either the treponema itself or its unique genetic material.

To do this, in medical practice are used:

• The study of the sample under a microscope in a dark field - dark field microscopy.
• Direct immunofluorescence. This is a modification of dark-field microscopy.
• Search for treponema DNA fragments by polymerase chain reaction (PCR).

For dark-field microscopy, discharge is taken from an accessible suspicious focus. With a positive result, live mobile spirochetes are visible in the eyepiece. The direct fluorescence method uses the same material as dark field microscopy. The sample is fixed with paraffin. And anti-treponemal antibodies pre-labeled with a fluorescent dye are applied to it. If the material contains the causative agent of syphilis, immunoglobulins bind strongly to proteins on the surface of the microbe and glow in ultraviolet light. To notice such a glow is quite easy.

These studies are cheap, have high specificity, but low sensitivity.

For a reliable result, it is necessary that the sample contains at least 1000 - 100,000 microbial bodies. And for dark-field microscopy, it is important that they are alive and moving. The PCR method allows you to give an accurate result if there are at least 10 spirochetes in the test sample. The specificity reaches 100%, so doubt Can a syphilis test be false positive? in this case it shouldn't.

However, if you do not follow the sampling methodology or make a technical error during the study, you can get a false negative result. And this is a significant drawback. The cost of research is also quite high.

Many women are interested in whether the hCG analysis can be erroneous. Chorionic gonadotropin usually appears in the urine during pregnancy. This hormone is produced when a fertilized egg attaches to the uterine wall. Such a study reveals pregnancy in a few days.

The strip test is also based on the amount of gonadotropin, but it often turns out to be defective. Therefore, it is better to donate blood for hCG, since this study is more reliable and gives correct results in 99% of cases. In some cases, the test may give a false positive or false negative result. Therefore, it is better to figure out whether a blood test for hCG can be wrong.

Reasons for a false negative

This analysis is highly accurate. At the same time, the human factor cannot be excluded, since the person who conducts the study may make a mistake. However, situations where laboratory assistants made a mistake are rare. Often, doctors interpret a positive test result as evidence of pregnancy, which is not entirely correct. For an accurate result, it is better to donate blood several times (about 1 time per week). In a pregnant woman, the amount of hCG will increase with each analysis by 2-3 times. If the concentration of chorionic gonadotropin remains at the same level, then this may indicate an ectopic or missed pregnancy.

Chorionic gonadotropin is found in the blood of all people. However, in pregnant women, the level of this hormone is 2-3 times higher than in non-pregnant women.

An incorrect result of an analysis with a low hormone content can be in the following cases:

1. Too short a pregnancy. Blood tests for hormones have a certain degree of sensitivity to gonadotropin. Usually, the required concentration of the hormone appears only by the 5th day of the delay in menstruation. Before this period, most tests will not show pregnancy. There are some studies that determine the presence of a fertilized egg in the uterus as early as 10 days after conception. They can be carried out for 1 day of delayed menstruation. But before this period, pregnancy cannot be detected, since the amount of hCG in the blood is too low.
2. Pathological course of fetal development. If the pregnancy is ectopic, or there is a threat of miscarriage, then a very small amount of the hormone is produced, and it cannot be determined.
3. Placental insufficiency or weak implantation of the fetus to the uterine wall. In these cases, the body produces very little human chorionic gonadotropin, so the test is not able to detect pregnancy, despite its presence. The same result is possible with late attachment of the embryo to the walls of the uterus.

Reasons for a false positive result

The test for hCG can also be wrong in cases where too much human chorionic gonadotropin is formed in the body of a non-pregnant woman. This is a serious hormonal disorder. Then a pregnancy blood test can give false positive results.

An increased amount of chorionic gonadotropin can be produced by a woman's body in diseases of the pituitary gland, as well as in tumors of other organs.

A high level of this hormone can be observed with pituitary adenoma. Usually these tumors are hormonally active. Those who have adenomas often suffer from endocrine disorders that lead to an increase in gonadotropin. In this case, the hormone is produced not by the tissues of the chorion (embryonic membranes), but by the cells of the pituitary gland.

A false result of the analysis and an increased content of chorionic gonadotropin, not associated with pregnancy, can be observed in malignant tumors. Analysis for hCG is often a tumor marker. An increase in gonadotropin may indicate the following diseases:

• mammary cancer;
• lungs' cancer;
• ovarian cancer;
• cancer of the stomach and liver.

In addition, an increase in the hormone may indicate neoplasms such as chorionic carcinoma and hydatidiform mole. Chorionic carcinoma is a tumor of the uterus that develops after a previous pregnancy. At the same time, chorionic villi remain in the uterus, which then degenerate into a malignant formation. Chorion particles can continue to produce hormones.

Bubble skid is a pathology of pregnancy development that begins in the early stages. Due to defective fertilization of the egg, tissue in the form of bubbles grows in the uterus instead of the placenta. At the same time, the embryo dies, but the pathological formation grows and continues to produce the hormone.

This suggests that an increase in chorionic gonadotropin, not associated with pregnancy, may indicate serious pathologies that require urgent treatment.

Of course, not always a false positive result of the analysis indicates tumors and other dangerous diseases. Most often, an increase in chorionic gonadotropin is associated with hormonal failure. In middle-aged women, this hormone rises in the period before menopause.

A false test result may be in a woman who has recently undergone an artificial termination of pregnancy. In this case, the hormonal background has not yet had time to return to normal.

The result of the analysis is incorrectly defined as positive when taken orally or injected with preparations containing human chorionic gonadotropin. These drugs include:

• Profazi;
• Prerotten;
• Human gonadotropin;
• human chorionic gonadotropin;
• Choriogonin;
• Horagon;
• Ovitrelle.

These drugs are quite often used in the treatment of infertility and before the IVF procedure, so the likelihood of an error due to the medication is quite high. If the patient underwent a course of therapy with similar drugs, this must be reported to the laboratory assistant. Other medications, including hormonal contraceptives, usually do not distort the results of a pregnancy test.

What to do with a false result of the analysis

You should know what to do if the result of a blood test gives positive or negative results that are in doubt.

You can re-test. In this case, it is necessary to exclude the use of drugs with choriogonin. Usually a re-analysis is done after a few weeks.

Additional research can also be done. For example, take a urine test for chorionic gonadotropin. You can use the test of two strips. Ultrasound will help confirm or refute pregnancy. It shows gestation at 5-7 obstetric weeks.

If the pregnancy is not confirmed by any other tests, but the chorionic gonadotropin in the blood continues to be high, the patient must undergo a comprehensive examination. You should contact an endocrinologist, gynecologist, mammologist and oncologist. It is necessary to undergo a series of tests that will reveal the function of the pituitary gland and ovaries. In addition, the doctor may prescribe a pelvic ultrasound and mammography.

A high level of gonadotropin production in a non-pregnant woman may be the result of a temporary hormonal failure. But sometimes it can indicate serious diseases that require treatment. In addition, a large amount of this hormone does not pass without a trace for the body. An elevated level of hCG leads to the appearance of luteal cystic formations in the ovaries. Most often they disappear on their own. But in some cases, cysts can grow to large sizes, which threatens to rupture and cause acute pain.

In contact with

In May 2016, it became known about the complete and final collapse of one of the most sensational start-ups in the field of healthcare - the Theranos project. The company promoted a technique for detecting 240 diseases by a drop of blood from a finger using its own Edison device. The founder and head of the project, a young American, Elizabeth Holmes, admitted that the test results sent to hundreds of thousands of patients were incorrect, and announced the mailing of corrected results.

The story is unusual from all angles, but what is most striking is the scale of the "mistake" - perhaps something that laboratory diagnostics has not yet seen. And how often in ordinary life do we encounter analysis errors and why do they happen at all? Who is to blame for them - the laboratory assistant, the failure of the equipment, or maybe even the patient himself? MedAboutMe understood the nuances of laboratory diagnostics.

Most often, staff errors are associated with their low qualifications. For example, you can talk about errors in sampling:

• Too tight tourniquet, incorrect body position can affect the results of studies of carbohydrate, lipid metabolism, etc.
• Violations of technology: for example, the use of conventional test tubes when testing blood for glucose leads to the fact that its level decreases by 10% after 20 minutes, that is, long before the end of testing. And if the procedure for changing tubes is violated, a reagent that should not be there can get into the sample, which affects the results.

Errors in the documentation are associated with illegible records and incorrect identification of the patient. Cases of giving test results to the wrong person are not uncommon in laboratories.

Separately, it is necessary to point out the violation of the temperature regime for the delivery and storage of samples. For example, the sampling of biomaterial for some complex analyzes may be carried out in a branch of a large network of laboratories or in a polyclinic, after which the blood must be delivered to the central department, where there is a possibility for its analysis. That is, the sample must move along the street - in winter at low temperatures or in summer at high temperatures. And, for example, an analysis for adrenocorticotropic hormone requires the use of deep freezing of a blood sample, and the cooler bag in which the samples are transported maintains a temperature of at least -3-4 ° C. In addition, it is not uncommon for samples to arrive at the central office with a delay - due to the lack of a special delivery service, for example - which also increases the risk of an erroneous result.

Finally, errors associated with the low qualification of personnel are possible during the actual analysis. Violation of sterility standards, contamination (contamination) of samples, improper preparation of reagents and other technological errors - all of them also increase the risk of obtaining an unreliable result.

Viral hepatitis C is considered the most dangerous viral disease, which usually occurs in a severe and complex form. To identify the disease, doctors prescribe to patients a series of tests that contribute to the correct diagnosis. Their passage is mandatory for every patient, because without a confirmed diagnosis, the doctor does not have the right to prescribe complex treatment. Often, after receiving the results, the doctor tells the patient that he has a false positive test for hepatitis C - this means that the person does not suffer from inflammation of the liver, even if the results of the tests performed do not "think" so. Why is sometimes an incorrect diagnosis result observed, and how to determine the absence of a disease in a patient?

Hepatitis C is an infectious lesion of the liver, which can occur in two forms (acute or chronic). The causative agent of the disease is the HCV virus, which today has a large number of species and forms. Since hepatitis C is considered the most dangerous pathology among all types of hepatitis, its treatment should be carried out soon after the onset of symptoms. However, symptoms are not always present in an infected person after a dangerous virus enters the liver. This significantly spoils the health of the inflamed organ, and also negatively affects the general well-being of the patient.

This disease can develop in any person, so people need to be examined by a therapist every six months, as well as take tests in order to detect liver damage in a timely manner.

The complexity of hepatitis C lies in the fact that the disease virus mutates quickly. That is why in the modern world there is no medicine that can completely cure liver disease, as well as restore its inflamed tissues and cells. According to doctors, only 20% of patients managed to completely cure the chronic form of hepatitis C.

Who needs regular blood tests to check for hepatitis?

The test is usually carried out every six months for the following categories of people:

• people who often visit beauty salons;
• tattoo parlor workers;
• after surgery;
• before transfusion of donor blood;
• frequent dental treatment;
• if a relative or close person is infected with the C virus;
• when working with the blood of patients.

It is also required to take an analysis for the determination of hepatitis C during pregnancy, when there is a risk of infecting the child with the disease.

How to determine the development of liver pathology? To do this, a person must identify one or more symptoms of hepatitis C.

These include:

• frequent nausea, especially active after eating;
• deterioration or change in stool;
• pain in the joints;
• slight pain in the right hypochondrium of the body;
• yellowing of the skin in humans.

Many people who have been told by doctors about a false positive result of the analysis are upset - you should not do this, since you first need to wait for a second analysis, which will confirm or refute the diagnosis.

Every patient who has been found to have a false-positive or positive test result requires mandatory verification of these data. To do this, doctors use additional diagnostic methods that are more truthful and reliable.

A false positive result is quite common - it requires mandatory testing, since hepatitis C is considered the most dangerous disease among all forms of this disease. Therefore, the discovery of a positive analysis is perceived by many as a sentence.

Doctors say that several reasons can cause incorrect testing of the disease, so it is unacceptable to immediately prescribe treatment, otherwise it will cause serious harm to the patient.

Several specialists of a narrow profile can make the correct diagnosis and prescribe treatment for hepatitis C.

These include:

• an infectious disease specialist who examines a patient during an acute form of the disease;
• gastroenterologist prescribing treatment for advanced disease;
• hepatologist.

The first diagnosis of the patient is carried out using the enzyme immunoassay method, thanks to which it is possible to identify markers of the disease, as well as to detect the pathology virus. ELISA is performed by determining the concentration of antibodies that, in case of infection, are present in the blood of an infected person, taken from a vein. However, this research method is not always reliable. For example, if a person has previously had hepatitis C, antibodies to the pathogen will remain in his blood for several years. Or the detection of antibodies is associated with another viral disease, the development of which does not occur in the liver, but in another organ.

In any case, ELISA is considered the primary analysis, with the help of which a woman, man or child will be able to identify the hepatitis C virus, as well as assess the general condition of the liver.

If the doctor informed the patient about a false positive analysis, he needs to undergo some clarifying diagnostic methods. They are usually prescribed if a person has no symptoms of hepatitis C, especially digestive disorders or yellowing of the skin.

Additional diagnostic methods include:

• blood donation;
• definition of a chain reaction;
• Ultrasound of the liver and other nearby organs.

Usually, it is the ELISA analysis that is false positive, so it is important to find out how it is decoded.

Using the ELISA method, it is possible to determine the total amount of antibodies to the causative agent of the disease, which are produced by the human immune system shortly after the onset of inflammation of the liver.

Antibodies are divided into several types:

• IgM type, which is produced during the acute form;
• IgG type that develops during advanced hepatitis C.

IgM antibodies during laboratory tests are detected only 2 weeks after the onset of infection of the body - they will be in the blood for 3-5 months. IgG antibodies appear in the patient's blood much later, but after the disease is completely cured, they remain in the body for 8-10 years after the death of the pathogen.

A negative result after the ELISA test indicates the complete absence of antibodies, which means that the patient is absolutely healthy. However, this result does not take into account the last 2 weeks of the patient's life, in which he, too, could catch a dangerous pathogen. In 14 days, antibodies usually do not have time to develop immunity, so the analysis will show an earlier infection.

A positive result indicates that antibodies to the pathogen are present in the blood. This indicator indicates the course of an advanced form of the disease, and also indicates its recent cure, or it indicates that the patient is carrying a virus that has not yet had time to become active in the liver.

Sometimes the ELISA shows a false positive result, which is caused by a number of factors. The main one is considered to be a laboratory error, poor-quality reagents or improper blood donation, which violated its composition.

If an error was made during the ELISA and the result of blood donation is false positive, the patient needs to conduct a number of additional studies. First of all, the patient is assigned PCR.

It is required to:

• clarify the result of the ELISA analysis;
• determine the stage of pathology;
• identify hepatitis C from other types of disease;
• control the treatment.

However, PCR also sometimes causes a false positive result with the development of a cross reaction.

The patient will also need to undergo a liver biopsy. Such an analysis will help determine the concentration, content and activity of the causative agent of hepatitis C, which will allow you to quickly and accurately diagnose the disease. However, a biopsy is prescribed only in a severe case, when the pathogen has already affected most of the liver cells.

Attention! The health organization requires that hepatitis C be tested three times.

This is done by any of the most accessible methods that help identify the following indicators of the development of hepatitis C:

• blood concentration of the HCV virus;
• amount of transaminase;
• histological problems occurring in the liver;
• type of pathogen;
• viremia level.

Judging by the reviews, the full diagnosis of hepatitis C is carried out with the help of several specific examinations.

These include:

• analysis for IL-28B - helps to determine the genotype of the pathogen;
• conducting a blood test - helps to determine the level of red blood cells, monocytes and other blood cells;
• conducting a biochemical analysis - it helps to identify bilirubin, AST, ALT and other components.

Also at the same time, it is necessary to evaluate the work of the liver by albumin, coagulogram and fractions.

You can notice a false positive result after donating blood in the process of bearing a fetus. Practice shows that after ELISA in 15% of cases in pregnant women, an incorrect result is observed.

There are many reasons for this - these include:

• the appearance of tumors that have a benign and malignant course;
• development of oncology;
• neoplasms in organs;
• malfunctions in the functioning of the immune system;
• the presence in the blood of a large number of chemicals after taking the drugs;
• immunosuppression - suppression of immunity for one reason or another;
• early diagnosis even during the onset of the incubation period of the virus;
• autoimmune hepatitis;
• respiratory diseases that occur in an acute form;
• increased content of cryoglobulin in the body.

As information from the forum shows, it is these conditions of the body that cause a change in the results of the analysis of hepatitis C, so the patient will need to repeat diagnostic measures.