Q: pancreatic cancer: oncologist says ca19-9 blood tests are showing false negative (<37)results. how does he know for sure there is cancer?

More information: Hi. To me, that looks like very good information (the tumor marker is undetectable). If he has information otherwise, he needs to explain it to you. Was your CA 19-9 elevated before surgery, chemo + radiation? If so, and it's negative now, based on the information available, I'd say that's exactly the result you'd like to see! Ask him to explain his position. Good luck!

Q: i experience gi symptoms like diarrhea, gas, and bloating after gluten intake - even very small amounts. blood tests for celiac disease were all normal. can it be a false negative? and if so can an endoscopy pick up on those false negatives?

: Even if you do not have celiac disease, you may try gluten free diet to see if that helps with your symptoms. For additional information, you may visit this site: https://www.niddk.nih.gov/health-information/digestive-diseases/gas-digestive-tract/eating-diet-nutrition. Wish you good health!

Q: is it possible to have 5 false positive hpts?(different brands). i went to the drs & their test was neg. blood tests will confirm wed, but i'm curios.

Mega-rare: There is the occasional woman who does not produce the beta-hcg subunit like the vast majority of the population, so routine testing for it will reflect negative even though pregnant. Before decide this is you, I have seen two cases in ~30 years, so (-) is likely (-) and you need to try again and/or consult a fertility specialist for evaluation.

Q: positive diagnosis (scleroderma, polymyositis) with negative blood tests? is that common?

PM/Scl: The paradox of rheumatologic diseases is that there are more lab tests in this area than any other, and they of relatively less value compared to the history and physical findings than in other fields. If your rheumatologist is comfortable with the diagnosis of "scleromyositis", which usually features anti-pm/scl, i'd accept it even with a single negative result, and proceed.

Q: how reliable are blood tests that look for monoclonal gammopathy in elevated imm levels ? are false negatives possible?

Very: the testing for gammoparhy at at the present time is very sensitive. The means by how this gets measured and analyzed is so sensitive that I can t out all of the different Antibody types.

Q: what are the different types of common blood tests?

Too broad a question: There are literally thousands of blood tests available. The most common are a CBC and a chem 20. The CBC measures your hemaglobin and hematocrit and blood cell count. The chem 20 is the 20 most common chemistries in the blood, including sodium, chloride, creatinine, triglycerides, cholesterol, etc.

Q: how often are d dimer blood tests falsely negative?

Decision levels: There is no simple "positive" or "negative" for a D-dimer. A value is reported to a physician and he/she uses this to gauge the likelihood of a thrombus / DIC.

Q: negative herpes culture and blood tests; pretty accurate?

Likely OK.: I don't know what your history is but if you had/have a herpes infection, you likely would have noticed skin lesions that could be irritating at some point in time. Many times there can be no symptoms but if you have this there would be some kind of outbreak at some point in time. The tests include tzank prep. Of scrapings that show giant cells, cultures are pos. In 48-96 h, elisa+pcr are great.

Question 1

ive been diagnosed with antiphospholipid syndrome, with positive blood tests. could clexane make your blood results negative, if you retested it? give you a false negative?

Accepted Answer

Not really : This drug does not interfere with symptoms of antiphospolipid syndrome

Question 2

do blood tests rule out temporal arteritis? or could there be a false negative?

Accepted Answer

: The typical blood tests you order when you are concerned about temporal arteritis are CBC, ESR and CRP. They are not specific to temporal arteritis instead the physician would be looking for blood tests signs of inflammation and anemia. But, if the test were all normal, it would likely not be temporal arteritis.

Question 3

pancreatic cancer: oncologist says ca19-9 blood tests are showing false negative (<37)results. how does he know for sure there is cancer?

Accepted Answer

More information: Hi. To me, that looks like very good information (the tumor marker is undetectable). If he has information otherwise, he needs to explain it to you. Was your CA 19-9 elevated before surgery, chemo + radiation? If so, and it's negative now, based on the information available, I'd say that's exactly the result you'd like to see! Ask him to explain his position. Good luck!

Question 4

i experience gi symptoms like diarrhea, gas, and bloating after gluten intake - even very small amounts. blood tests for celiac disease were all normal. can it be a false negative? and if so can an endoscopy pick up on those false negatives?

Accepted Answer

: Even if you do not have celiac disease, you may try gluten free diet to see if that helps with your symptoms. 
For additional information, you may visit this site: https://www.niddk.nih.gov/health-information/digestive-diseases/gas-digestive-tract/eating-diet-nutrition.
Wish you good health!

Question 5

is it possible to have 5 false positive hpts?(different brands). i went to the drs & their test was neg. blood tests will confirm wed, but i'm curios.

Accepted Answer

Mega-rare: There is the occasional woman who does not produce the beta-hcg subunit like the vast majority of the population, so routine testing for it will reflect negative even though pregnant. Before decide this is you, I have seen two cases in ~30 years, so (-) is likely (-) and you need to try again and/or consult a fertility specialist for evaluation.

Question 6

positive diagnosis (scleroderma, polymyositis) with negative blood tests?  is that common?

Accepted Answer

PM/Scl: The paradox of rheumatologic diseases is that there are more lab tests in this area than any other, and they of relatively less value compared to the history and physical findings than in other fields. If your rheumatologist is comfortable with the diagnosis of "scleromyositis", which usually features anti-pm/scl, i'd accept it even with a single negative result, and proceed.

Question 7

how reliable are blood tests that look for monoclonal gammopathy in elevated imm levels ? are false negatives possible?

Accepted Answer

Very: the testing for gammoparhy at at the present time is very sensitive. The means by how this gets measured and analyzed is so sensitive that I can t out all of the different Antibody types.

Question 8

what are the different types of common blood tests?

Accepted Answer

Too broad a question: There are literally thousands of blood tests available. The most common are a CBC and a chem 20. The CBC measures your hemaglobin and hematocrit and blood cell count. The chem 20 is the 20 most common chemistries in the blood, including sodium, chloride, creatinine, triglycerides, cholesterol, etc.

Question 9

how often are d dimer blood tests falsely negative?

Accepted Answer

Decision levels: There is no simple "positive" or "negative" for a D-dimer. A value is reported to a physician and he/she uses this to gauge the likelihood of a thrombus / DIC.

Question 10

negative herpes culture and blood tests; pretty accurate?

Accepted Answer

Likely OK.: I don't know what your history is but if you had/have a herpes infection, you likely would have noticed skin lesions that could be irritating at some point in time.  Many times there can be no symptoms but if you have this there would be some kind of outbreak at some point in time.  The tests include tzank prep. Of scrapings that show giant cells, cultures are pos. In 48-96 h, elisa+pcr are great.

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Doctor answers about:

How common is false negative blood tests

A member asked:

Ive been diagnosed with antiphospholipid syndrome, with positive blood tests. could clexane make your blood results negative, if you retested it? give you a false negative?

A member asked:

Do blood tests rule out temporal arteritis? or could there be a false negative?

A member asked:

Pancreatic cancer: oncologist says ca19-9 blood tests are showing false negative (<37)results. how does he know for sure there is cancer?

A member asked:

I experience gi symptoms like diarrhea, gas, and bloating after gluten intake - even very small amounts. blood tests for celiac disease were all normal. can it be a false negative? and if so can an endoscopy pick up on those false negatives?

A member asked:

Is it possible to have 5 false positive hpts?(different brands). i went to the drs & their test was neg. blood tests will confirm wed, but i'm curios.

A member asked:

Positive diagnosis (scleroderma, polymyositis) with negative blood tests? is that common?

A member asked:

How reliable are blood tests that look for monoclonal gammopathy in elevated imm levels ? are false negatives possible?

A member asked:

What are the different types of common blood tests?

A member asked:

How often are d dimer blood tests falsely negative?

A member asked:

Negative herpes culture and blood tests; pretty accurate?

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