There are many different ways to test for parasites. Evidence of parasites can be found in stool samples, urine examined under a microscope, or by analysis of our blood’s immune system chemicals.
But in some situations, a blood test is the most accurate and only practical option for finding certain parasites. To help you understand when to use blood parasite testing, we’re going to explore the best and the worst blood parasite tests, as well as some reasons to choose a blood parasite test over non-blood parasite tests.
Quick facts about parasite blood tests:
There are 4 different types of blood parasites tests that are commonly used. We give an overview of each test below, with links to in-depth articles about each test.
Serology blood testing looks for our immune system’s chemical response to parasites. This is done by looking for antibodies chemicals in our blood. Antibody chemicals are unique enough that they can be recognized as a response to a specific parasite.
The best feature of serology is that you can test your blood, and it will tell you if your immune system has responded to a non-blood parasite. Serology can see if our immune system has reacted to a parasite in our intestines, our blood or even our urine.
Unfortunately, serology testing can’t always tell the difference past exposure to a parasite, and current infection of a parasite. Also, your serology test needs to check specifically for each type of parasite. So if the antibody test doesn’t look for a parasite, you won’t have know if you’ve been exposed to that parasite.
It’s also possible to have rapid diagnostic tests (RDTs) for some parasites. For instance, malaria has some great field testing options like this one. RDT malaria tests are very useful when travelling in a an area with malaria, that has hard to access malaria testing facilities. The W.H.O has is a great explanation of how the RDT tests work.
Full article: serology parasite testing
This test is also known as the peripheral blood smear (PBS), or the blood ova and parasite (blood o&p)
The blood smear parasite involves carefully smearing some blood onto a slide, and then a technician (ideally a parasitologist), examines it under a high powered microscope. There are both thin film smear and thick film smear versions of this, and some test processes will add a Giemsa stain to make it easier to identify different types of parasites.
The peripheral blood smear test is most useful for finding parasites that live in our blood. Malaria is the most important parasite found in the blood via this microscopy method. But there are other parasites that can be found with this test, such as:
Beyond finding parasites, the blood smear parasite test can also find hematological disorders. Hematological examination can be a way to find certain deficiencies or potential diseases. Our thin film blood parasite test looks for parasites and potential hematological disorders.
The Complete Blood Count (CBC) test is a routine blood test to see if any part of your blood looks abnormal. And even though the complete CBC does not tests for parasites, indirect evidence of parasites may be revealed by this test. Depending on how high or low you test for certain things, this routine blood work can justify further testing for parasites.
A few key parts of the CBC blood test that may be indicate parasite problems:
This test will never, ever, directly show that you have a parasite infection. But because people routinely take the CBC test for other medical reasons, it’s useful to know when your CBC test may justify parasite testing.
Read our full article: Do Parasites Show Up In A CBC Test?
Live blood analysis (LBA) uses high-resolution dark field microscopy to look for parasites. It’s practitioners claim they can observe a wide range of parasites…unfortunately, there is not much evidence to back these claims, and LBA is an extremely controversial blood test for parasites.
Some websites about LBA claim they can see specific parasites in the blood, even though those specific parasites spend their life in the intestines, not inside our blood.
Other potential issues with live blood analysis include:
the lack of standardized protocols and guidelines for conducting Live Blood Analysis
the potential for misdiagnosis and incorrect treatment
While there may be some competent practitioners out there, Parasites.org recommends almost any other blood parasite test over live blood analysis.
DNA blood parasite testing is currently used in some niche situations like Toxoplasmosis, . And in those specific situations, you can find parasite tests that use PCR to analyze parasite DNA in your blood. There may also be rapid diagnostic PCR tests available.
Now let’s go through a few practical examples of good ways to look for specific parasites. We’re going to see if a blood parasite test makes sense, or if there are better options.
The best parasite test depends on your unique situation. As someone who lives in downtown Denver, I don’t have to worry much about blood parasites. Intestinal parasites are much more likely to be a problem when I am swimming in rivers or lakes in the mountains…or from contact with other people. I generally think our gut parasite test, or the gut parasite test upgraded with a bacteria swab are the most useful, most of the time. For someone living in the USA, there are only very niche situations where I would prefer a blood parasite test, or perhaps a urine test over an intestinal parasite analysis. To get a broader view of non-blood parasite tests, read our article about the accuracy of the most common parasite tests. But of course, please work with your doctor to figure out what parasite test may be best for you.
Serology tests are most available from labs like Labcorp, Quest Labs, or your local doctor. In practice, serology tests aren’t used very often. My favorite 2 serology tests for parasites are for Toxoplasmosis (eg. for pregnant women around cats), and Toxocara (which may cause blindness, and is designated a neglected parasite disease in the USA). But of course, please work with your doctor to figure out what parasite test may be best for you.
Evan Jerkunica, Parasites.org's founder is happy to help. To get your questions answered, you can: