TOXOPLASMOSIS - ERROR PRONE DIAGNOSIS
Dr.T.V.Rao MD
It was my young years as a Microbiologist at a corporate hospital at Chennai , heading the department and responsible for supervising 100’s diagnostic serology reports, A real challenge came when Dr Mrs JAYA RAGHAVAN ( name Changed ) running 3 rd month of pregnancy (34 years )a Paediatrician working in USA walks to my chamber with report signed by me as Toxoplasma serology positive for IgG and IgM the test was done by the senior technologist with Abbott Tube ELISA system the kits were imported from Singapore and made in USA . She wishes to know can she go for termination of pregnancy on this report a great puzzle for me, I am frank enough to say, I sign nearly hundreds of reports with a trust in my technicians, and quality of materials available and I can not let down the kits which are really precious, I said kindly get the test in another laboratory accredited with quality control, I have sent her to Dr Ramamurthy's pathology diagnostic center Chennai , and she returned after two day with a negative result for IgM and IgG, She never complained on matter, about the test, I said Madam I will repeat the test myself in the next run I did it, the result is truly negative , I said sorry we disturbed your peace, she accepted the serological tests are deceptive, and error prone and need the good support of clinical Microbiologist I realised very soon we should have a good cooperation and quality controls when we do any serological test and none of the laboratories are 100% accurate in diagnosis. Technical errors are subject to correction needs the attention of supervisory staff for better reporting .
I have followed up with many serological tests in my career , and serology continues to be very difficult division and results need to be repeated whenever we pronounce a positive diagnosis when the decision may be catastrophic , as it is the termination of pregnancy with Toxoplasmosis in pregnancy in the early term, or HIV serology reporting
I realised that Clinicians order the tests at random on the effluence of the patients, however one should be cautious when you do a screening for Infections which can damage a fetus during pregnancy as many are doing To/R/C/H screening
Testing for Toxoplasmosis is fraught with errors look to the literature
When might a blood test be recommended?
The blood test for toxoplasmosis may be carried out if there's a chance you have the condition and you have symptoms of the infection, or you're at risk of serious complications of toxoplasmosis, people living with Cat as their pet Animal For example, the test may be recommended if you're diagnosed with HIV or are scheduled to have an organ transplant. In the UK, and many developed countries testing for toxoplasmosis isn't routinely carried out during pregnancy because the risk of picking up the infection while you're pregnant is very small and there are some concerns about the reliability of the test in pregnant women. It is true in many developing countries, where we do not get truly precise diagnostic kits, due to lack of sufficient workload few control parameters are used, and many private run laboratories use out dated kits, with false negatives, losing the value of test It's also not clear exactly how effective treatment during pregnancy is in stopping the infection spreading to the baby.A positive result means you've been infected with toxoplasmosis at some point, but doesn't necessarily mean you have an active infection. Catch 22 situation for clinician whether to recommend a termination of pregnancy if it is early trimester,
WHAT SEROLOGY REPORT MEANS IgG antibodies will stay in blood for life, protecting one from being infected again. IgM antibodies appear soon after you have been infected and then disappear, usually over a period of a few months.
If you have IgM antibodies, this indicates you have been infected relatively recently (probably within the past year), although it still doesn't determine for certain whether any symptoms you have are caused by toxoplasmosis.
Diagnosis during pregnancy
If pregnant and blood tests confirm you have a recent toxoplasmosis infection, you may need a further test to determine whether your unborn baby is also infected.
Amniocentesis is the most effective and commonly used test, and can be carried out any time from 15 weeks of pregnancy onwards. The sample will be tested for toxoplasmosis.India at the present have few centers to perform the testing and truly risky if done by a inexperienced professional Amniocentesis carries around a 1% risk of causing a miscarriage. The procedure can confirm whether your baby has the infection, but it can't determine whether the infection has caused any serious damage.
Diagnosis in people with a weak immune system
If one has a weakened immune system, routine blood tests for antibodies can produce a false-negative result. This is because it's possible your immune system won't produce antibodies to fight the infection. So often we get negative serology in AIDS patients with Active infection with Toxoplasmosis. And many are empirically treated with clinical experience
NEVER TO FORGET EVERY SEROLOGICAL TEST TO BE DONE WITH A PURPOSE Casual testing is counterproductive and to be done with wisdom
NO SEROLOGICAL TEST IS A GOLD STANDARD NEEDS WISDOM OF LABORATORY AND CLINICIAN To MAKE MAJOR DECISIONS
References Toxoplasmosis - Diagnosis NHS Choices
Dr.T.V.Rao MD Freelance reporter on Clinical microbiology
Dr.T.V.Rao MD
It was my young years as a Microbiologist at a corporate hospital at Chennai , heading the department and responsible for supervising 100’s diagnostic serology reports, A real challenge came when Dr Mrs JAYA RAGHAVAN ( name Changed ) running 3 rd month of pregnancy (34 years )a Paediatrician working in USA walks to my chamber with report signed by me as Toxoplasma serology positive for IgG and IgM the test was done by the senior technologist with Abbott Tube ELISA system the kits were imported from Singapore and made in USA . She wishes to know can she go for termination of pregnancy on this report a great puzzle for me, I am frank enough to say, I sign nearly hundreds of reports with a trust in my technicians, and quality of materials available and I can not let down the kits which are really precious, I said kindly get the test in another laboratory accredited with quality control, I have sent her to Dr Ramamurthy's pathology diagnostic center Chennai , and she returned after two day with a negative result for IgM and IgG, She never complained on matter, about the test, I said Madam I will repeat the test myself in the next run I did it, the result is truly negative , I said sorry we disturbed your peace, she accepted the serological tests are deceptive, and error prone and need the good support of clinical Microbiologist I realised very soon we should have a good cooperation and quality controls when we do any serological test and none of the laboratories are 100% accurate in diagnosis. Technical errors are subject to correction needs the attention of supervisory staff for better reporting .
I have followed up with many serological tests in my career , and serology continues to be very difficult division and results need to be repeated whenever we pronounce a positive diagnosis when the decision may be catastrophic , as it is the termination of pregnancy with Toxoplasmosis in pregnancy in the early term, or HIV serology reporting
I realised that Clinicians order the tests at random on the effluence of the patients, however one should be cautious when you do a screening for Infections which can damage a fetus during pregnancy as many are doing To/R/C/H screening
Testing for Toxoplasmosis is fraught with errors look to the literature
When might a blood test be recommended?
The blood test for toxoplasmosis may be carried out if there's a chance you have the condition and you have symptoms of the infection, or you're at risk of serious complications of toxoplasmosis, people living with Cat as their pet Animal For example, the test may be recommended if you're diagnosed with HIV or are scheduled to have an organ transplant. In the UK, and many developed countries testing for toxoplasmosis isn't routinely carried out during pregnancy because the risk of picking up the infection while you're pregnant is very small and there are some concerns about the reliability of the test in pregnant women. It is true in many developing countries, where we do not get truly precise diagnostic kits, due to lack of sufficient workload few control parameters are used, and many private run laboratories use out dated kits, with false negatives, losing the value of test It's also not clear exactly how effective treatment during pregnancy is in stopping the infection spreading to the baby.A positive result means you've been infected with toxoplasmosis at some point, but doesn't necessarily mean you have an active infection. Catch 22 situation for clinician whether to recommend a termination of pregnancy if it is early trimester,
WHAT SEROLOGY REPORT MEANS IgG antibodies will stay in blood for life, protecting one from being infected again. IgM antibodies appear soon after you have been infected and then disappear, usually over a period of a few months.
If you have IgM antibodies, this indicates you have been infected relatively recently (probably within the past year), although it still doesn't determine for certain whether any symptoms you have are caused by toxoplasmosis.
Diagnosis during pregnancy
If pregnant and blood tests confirm you have a recent toxoplasmosis infection, you may need a further test to determine whether your unborn baby is also infected.
Amniocentesis is the most effective and commonly used test, and can be carried out any time from 15 weeks of pregnancy onwards. The sample will be tested for toxoplasmosis.India at the present have few centers to perform the testing and truly risky if done by a inexperienced professional Amniocentesis carries around a 1% risk of causing a miscarriage. The procedure can confirm whether your baby has the infection, but it can't determine whether the infection has caused any serious damage.
Diagnosis in people with a weak immune system
If one has a weakened immune system, routine blood tests for antibodies can produce a false-negative result. This is because it's possible your immune system won't produce antibodies to fight the infection. So often we get negative serology in AIDS patients with Active infection with Toxoplasmosis. And many are empirically treated with clinical experience
NEVER TO FORGET EVERY SEROLOGICAL TEST TO BE DONE WITH A PURPOSE Casual testing is counterproductive and to be done with wisdom
NO SEROLOGICAL TEST IS A GOLD STANDARD NEEDS WISDOM OF LABORATORY AND CLINICIAN To MAKE MAJOR DECISIONS
References Toxoplasmosis - Diagnosis NHS Choices
Dr.T.V.Rao MD Freelance reporter on Clinical microbiology
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