My approach to testing for Tick-borne infection

What is a common-sense approach to testing for Tick-borne infection. I focus on the most common infections that I see a Lyme disease infection. I order a Lyme disease test as well as test for infections like Ehrlichia, Anaplasmosis, and Babesia. I don’t typically order Mycoplasma or Chlamydia unless there is evidence that there’s active infection. 

 

I order an ELISA test, which is also called Lyme titer.  I also order a western blot and IgG and IgM test. These are test where you need two out of three bands IgM bands. You need five out of 10 IgG bands to be called positive by the CDC criteria. These are bands that were identified and in 1994 at a consensus meeting in Dearborn Michigan.  These markers are protein that have been identified in Lyme disease infections.  For example, the 41 kDa band represents a protein contained in the tail of a spirochete.

 

I have not been ordering a C6 peptide or VlsE protein tests for Lyme disease as they are not as reliable as I would like.  None of these tests for Lyme disease are all that sensitive in my experience.  I have often had to use clinical judgement to diagnose and treat Lyme disease.

 

I also order IgG and IgM tests for co-infections with Babesia, Bartonella, Anaplasmosis, and Ehrlichia. I have not found PCR tests for these co-infections as helpful as I would like.

 

I have found a blood smear for Babesia not helpful if a patient has been sick more than 2 weeks.  

 

Some doctors have assumed Bartonella tests have been positive due to exposure to fecal matter from mites living on cats. I can’t be sure the cause of positive tests for Bartonella in patients with Lyme disease. 

 

I don’t typically ordered labs for infections such as tularemia or Brucellosis despite concerns by some of my colleagues. I have found treatment for Lyme disease would take care of these infections if they were present.

 

I typically do not sent bloods to a specialty lab if someone’s on a budget. I also do not send bloods to these labs if I am going to treat clinically.  

 

I also order extensive testing to rule other illnesses like a CBC, comprehensive metabolic profile, ANA, RA, thyroid, sed rate, vitamin B12 and D.    I may order a free T4 and free T3 if I am considering a thyroid condition.  I have found ANA frustrating as most of the ANA tests are false positive. A positive dsDNA supports the diagnosis of lupus. My patients don’t typically have three other conditions that would support the diagnosis of Lupus. I refer my patients to see a rheumatologist if there is a need to rule out lupus.

 

I typical order blood test for a tick-borne illness four weeks or 4 to 6 weeks after onset of their illness to increase the chances that I might get a positive test.  I have had to use clinical judgement to treat a tick-borne infection if my patient is sick for less than 4 weeks or if I suspect a false negative test,