Image of hand in surgical glove Covid 19 antibody test kit

OK, another game….Let’s pick something “low” complexity, and then counter with the first “high” complexity thing we think of…Ready??

Low complexity……..floating in your pool on a rubber raft.
High complexity…taking on Class V rapids in the Grand Canyon.
 
Got it? Easy huh? OK OK let’s do a few more…
 
Low complexity…driving a Kia to the grocery store.
High complexity…driving auto pilot in a Tesla X in Downtown LA.
 
Low Complexity….making a grilled cheese sandwich from the Betty Crocker cookbook.
High Complexity…making a grilled cheese sandwich from James Beard winner Nancy Silverton’s cookbook.
 
Low complexity…binge watching “Breaking Bad” on Netflix.
High complexity…binge watching “Northern Exposure” from old video cassettes.
 
Alright.. so.. how does this tie into Covid? Well, the drive-thru tests for antibody offered throughout Southern California are “point of care,”meaning the test is run right then and there from a finger stick. It does NOT require government approval since it is “CLIA” waived. 

CLIA stands for “Clinical Laboratory Improvement Amendments.” CLIA is federal agency that mandates their approval for a lab to run tests and charge for them. And to get CLIA approved is quite a process…we have gone through the process and it would have been easier to get approval to launch a spaceship a la Elon Musk. 

To allow some tests to be done in old fashioned physician offices, like urinalyses, pregnancy tests, and strep screens, CLIA “waives” the tests they feel are “low complexity.” The current generation of antibody tests are low complexity and thus CLIA waived and able to be done at the “point-of-service” instead of having to be couriered to a clinical lab.
 
Are moderate/high complexity tests more accurate? Kinda…Maybe. Depends on how you define “accurate.”
 
In general, they can pick up cases earlier or with a lower “count.” They are more complex to design and run, hence the term “moderate/high complexity.” And, of course more expensive. (You saw that coming right?)
 
Let’s illustrate with an example I know a lot about…food!

The grilled cheese from Betty Crocker IS a legit grilled cheese. And decent too. No false advertising there.

On the other hand- Nancy Silverton’s grilled cheese? OMG. I mean just the ingredients are high complexity….here they are verbatim:
 
•    1/3 Cup Olive Oil, Extra Virgin
•    2 ½ Tbsp. White Wine Vinegar
•    2 Tbsp. Kosher Salt
•    1 Tbsp. Freshly Cracked Black Pepper
•    2 Medium Yellow Onions, Sliced into 1/8-Inch-Thick Slices
•    ¼ Cup Whole Grain Mustard
•    8 oz. Gruyere cheese, sliced into 24-32 1/16 inch-thick slices
•    Whole country sourdough loaf

I could go thru the actual process but it would be easier to explain how to split an atom. Nevertheless at the end of the process, you also have a grilled cheese sandwich. Just unlike any you’ve ever had. 

The point is; both are grilled cheese. One is just high complexity. (Full disclosure-I do not receive a kickback from Nancy-but if you want to enjoy the best grilled cheese you’ve ever had I highly recommend her sandwich cookbook, Nancy Silverton’s Sandwich Book: The Best Sandwiches Ever–from Thursday Nights at Campanile.) 

Now we can compare that to the office pregnancy test. It is accurate and picks up the pregnancy a day or two after the missed menses. The OTC test from the drugstore may need you to be 3-5 days late. Both are low complexity. But the moderate/high complexity CLIA approved test can pick it up a bit earlier than either of those that are CLIA waived. It isn’t technically more accurate; just more sensitive. It picks up the hormones at a lower level.
 
You can see where this is going with Covid antibodies. The usual test available in the past through Caduceus and PDQ Urgent Care and More (and other facilities) is CLIA waived. It gives us two antibodies.. IgM -which tells us if you have had Covid, and also IgG which implies immunity. Despite what I read on both social media and mainstream media, it IS accurate. But it requires a decent antibody load to pick up the antibodies.

What is antibody load? It’s like having a single shot latte to wake up mid-day compared to a triple shot espresso. It’s easier to pick up caffeine if you are analyzing the triple shot compared to the single shot. A moderate/high complexity “caffeine test” can pick up the single shot, the low complexity just the triple shot.
 
We have partnered with KOS labs here in Orange County and Healgen Labs in Houston for a “New Improved” antibody test that is moderate/high complexity and thus requires CLIA approval. 

There are some differences between the new test and the current one being offered.
 
*The current test uses a finger stick, the new one needs a blood draw.
*The current test gives a same day answer, the new one takes overnight. 
*The current test has about a 10% false negative rate, the new one less than 5%.
*The current test picks up the antibodies 4-16 weeks out, the new one weeks earlier. 
*We of course bill insurance, but if you need to pay cash the current one costs $75, the new one is $85. 
 
As CMO I endorse the newer test if you are having the antibody test. 

We have been searching for the most accurate antibody test to offer our patients and this appears to be the gold standard.  It can still be drawn curbside. And of course, the sooner you find out if you are immune the better for all involved.

The better sensitivity and accuracy outweigh the overnight wait and the $10 price bump. We will now be using the “moderate/high complexity” test as the default. If you prefer the finger stick/same day/low complexity test we of course will honor that. We will keep both tests available.

And because I know I’ll get emails inquiring, I am not aware of this test being offered by other Orange County groups, but it may be. If they require a blood draw and an overnight wait, good chance they are offering the moderate/high complexity test. To be legal they would need to be partnering with a CLIA approved lab.
 
And of course the video visits are from the privacy of your home and the testing is from the comfort of your car.
 
Conclusions? 
1. If you want to know if you’ve had Covid, you need an antibody test looking for IGM.

2. If you want to know if you are immune, you need an antibody tests looking for IgG.

3. If possible have a “moderate/high complexity antibody test” in lieu of the low complexity version. We work hard to not run low on inventory, and I still ask EVERY Caduceus patient to have an antibody test.

4. So far, there has not been a reported new positive Covid test in a patient with a positive IgG–at least that I can find. A positive IgG should reassure that you are immune.

5. KNOW IF YOU’RE CONTAGIOUS (Swab)
    KNOW IF YOU’RE IMMUNE (Antibody via blood)
    Test.Test.Test.

 
Ok; let’s do one more…
 
Low Complexity….Reading this blog eating a bologna sandwich.
High Complexity…Reading this blog eating a Nancy Silverton grilled cheese…no way you’ll pay attention to the blog!


Gregg Denicola MD
Chief Medical Officer 
Caduceus Medical Group


 

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