Question/Statement: “My internist stated that the 'gold standard' for sarcoidosis is a bronchosomething or other--a biopsy.”

Answer: Although I am sure your internist has good intentions, the statement is not true. (see below).

Gold Standard Definition:

• In medicine, a 'gold standard test' is the diagnostic test that is regarded as definitive in determining whether an individual has a particular disease process. To meet this definition, the test must have the ability to definitively determine the presence or absence of a disease. The ‘gold standard’ is the single test that other tests are compared to.
• Of note, the term ‘gold standard’ is being replaced by ‘criterion standard test’ to mean the same thing. However, for the sake of the specific question/statement above, I will continue to use the older term.

Reasons for the answer:

• The definition of ‘gold standard’ refers to a single superior test. As you know, you can only have one best of anything. Therefore, stating that there is more than one gold standard for any disease (bronchoscopy or biopsy) is not compatible with the definition. For you Highlander (1986) fans out there, “There can be only one.”
• Secondly, there is no gold standard for Sarcoidosis. The definition of ‘gold standard’ requires that the test can definitively determine the presence or absence of a disease on its own. There are no tests for sarcoidosis that meets this criteria.
• Some people will inappropriately use the term ‘gold standard” to refer to the perceived best test. However, I would defer from this distorted definition because it is misleading. Following this erroneous rational gives a test more credit than it deserves and can lead to inaccurate conclusions.

Why is there no gold standard for Sarcoidosis?

• There is no single test to date that can definitively diagnose the disease. This is not too surprising given that the etiology remains unidentified. Even pathology samples, which are considered by many to be the best diagnostic option, are fraught with error.

Then how do you diagnose Sarcoidosis?

• Because there is no one single definitive test for sarcoidosis, the diagnosis is achieved via a combination of clinical, radiographic and histological findings.  Not every patient suspected of having sarcoidosis will need undergo risky invasive procedures. When noninvasive data is convincing enough, the diagnosis can be achieved. Obviously, this is not always the case and therefore more invasive procedures may be necessary to realize the diagnosis. I would recommend non invasive options first.

Here are a few references I found on a quick search (in regard to the specific question in red above):

“There is no “gold standard” of diagnosis but only support for the diagnosis”
http://www.baylorhealth.edu/proceedings/14_1/14_1_pierce.html

“There currently exists no gold standard to confirm the diagnosis of sarcoidosis.”
http://jem.rupress.org/cgi/content/full/203/2/359

“Owing to the absence of a diagnostic gold standard, sarcoidosis is a diagnosis of exclusion”
http://jada.ada.org/cgi/content/full/137/1/54

No single test can be relied on for a correct diagnosis of sarcoidosis.
http://www.medhelp.org/lib/sarcoid.htm

Sarcoidosis remains a diagnosis based on exclusion... A “gold standard” test to identify which patients require treatment when noncritical organs are involved would be useful.
http://www.nhlbi.nih.gov/meetings/workshops/sarcoid-wkgp.htm

Although there is no single gold standard test…
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1891789/

As there is no definitive “gold standard” for the diagnosis, sarcoidosis is essentially a diagnosis of exclusion.
http://medind.nic.in/jac/t04/i1/jact04i1p12.pdf