The first question is whether testing should be done at all. Some might think of Lyme disease as a multi system disorder causing at least moderate disability. Others might think of it as a wide spectrum disorder with symptoms ranging from very mild to severe. In a way it is philosophical question. Many persons suffer with varying manifestations of chronic Lyme infection. Many patients are "colonized" with Lyme spirochetes but not necessarily ill, or very subtly ill. One should not test at all unless treatment is desired based on an assessment of symptoms. Treating patients with minimal symptoms can still be a daunting process. In many such cases watchful waiting may be the best course.
Given that TBD (tick borne disease) is suspected, also called LBC (Lyme Boreliosis complex), (Note these terms are replacing the term chronic Lyme disease because of the increasing assumption of a poly-microbial syndrome), one must give careful consideration regarding the use of ancillary laboratory testing.
The first phase of testing is of course the history and physical exam.
As we move into the realm of lab tests the first priority is to document exposure to Borrelia burdorferi, the Lyme spirochete. Most patients have insurance. This means that tests at "mill labs" like Labcorp and Quest are covered. This is usually the starting place. These labs do a mediocre job with serological(antibody) tests, but appear to do a poor job with PCR testing. Don't order the standard Lyme antibody test. This means an ELISA test will be done. We know this is a poor screening test. Order a direct Lyme Western Blot test. This is a better, yet still poor test. It only reports 13/28 bands. Despite this, sometimes we get lucky. Labcorp and Quest will do serological tests for Ehrlichia, Bartonella and Babesia. Labcorp does a PCR for Anaplasmosis which is poor, while Quest does a serology test for Anaplasmosis which is better. The Ehrlychia test is the best of this group. The other tests cannot be relied upon for varying reasons. Positive results for Babesia, Bartonella and Ehrlichia when they do appear, not only provide evidence regarding these co-infections, but also provide good, indirect evidence of Borrelia infection as well.
The CD57 test is frequently ordered. This is available only through Labcorp. It's value remains controversial. Low levels tend to suggest immune suppression and possible chronic infection. The C3a and C4a complement tests are available also only from Labcorp. They provide clues of inflammation and therefore infection.
Sed rate and CRP are markers of inflammation. They are frequently elevated. When positive they are helpful.
ANA and RF indicate autoimmune issues. These are also frequently elevated and offer further evidence regarding secondary autoimmune effects.
B12 and folic acid are important. Low levels are common and may be associated with co-infections within red blood cells.
Vitamin D levels: OH 25, and Dihydroxy 1,25 levels may indicate evidence of L-form disease and are useful markers.
CBC is important. Low WBC counts may correlate with Ehrlichia and other tick borne infections. Routine chemistries are important to screen for liver function abnormalities and other metabolic issues.
We have been cost effective so far, assuming third party coverage.
If we want better data we must use speciality labs. These labs generally do not participate with insurance plans.
Lyme Western Blots from reference labs like IgeneX and Clongen are very helpful. The yield can be improved by first giving antibiotics and then performing the assays, especially after a Herx response.
Routine Blood PCRs for Lyme have a very low yield and are not cost effective.
Some physicians assume that co-infections are present and treat empirically, especially if serological evidence of Lyme has been obtained.
The next cost effective test is a blood smear. The presence of gram negative rods or cocco-bacillis suggests Bartonella. if confirmation is desired, a DNA extraction with a 16S DNA fingerprint can be obtained. A finding of Babesia on a blood smear would be great, but this is a low yield procedure.
A new 15 species PCR for Babesia and a 20 species PCR for Bartonella is available from Clongen and should be cost effective. The mill labs do serology for B. microti and IgeneX does serology for B. duncani. This gives a decent yield but misses many pathogenic strains. The FISH test for B. microti from IgeneX is a good test, but it adds extra expense and it only tests for one species.
Let me say a word about the C6 Bb ELISA test. Most LLMDS don't do it because of a low yield. First, it is highly specific. A positive result is better evidence than a positive Western Blot. Second, I view numeric index results differently. The 0.9 cutoff is conservative and was calibrated for acute Lyme, not chronic Lyme disease. Levels over 0.3 are very suggestive and levels over 0.4 correlate highly with the Lyme diagnosis. This test is always worth doing. Because it is quantitative it can be monitored over time during the course of therapy. It frequently "seroconverts" after antibiotics have been administered.
In summary, there are many diagnostic lab options. Many co-infections can be diagnosed empirically. You can work with you LLMD to determine which tests are most appropriate and which fit into your budget. It is OK to discus the cost and benefits of the various tests. I think a good physician who trusts his clinical abilities will often be comfortable working with less lab data. The problem remains that even the best tests frequently miss clinically significant infections; so negative results should not be used as a justification to not treat.
Many LLMDS seem to order large panels from specialty labs which cost thousands of dollars. I think a thoutful approach can save patients a lot of out of pocket expense.