Yield

What is the diagnostic yield of a pleural biopsy? The answer will depend upon the following:

The yield of the first pleural biopsy is reported to be 35-50% malignancy.

The yield of pleural fluid cytology ranges from 30-50%.

Let us first consider malignant pleural effusions. The reported percent range of diagnostic yield for pleural biopsy is 30-50%. The yield for fluid cytology is 30-50%.

The combined diagnostic yield of pleural biopsy and fluid cytology is approximately 66% in confirming the diagnosis of malignancy.

The sensitivity of pleural biopsy in tuberculous effusions has been reported to be in the range of 50-70%.

The yield of pleural fluid cultures for organisms is relatively small. Positive cultures for tuberculosis have been reported in approximately 20% of known cases.

The Reported Diagnostic Sensitivity Reported in Tuberculous Effusions
Pleural biospy 30-50%
Fluid culture 15-20%
Pleural tissue culture 50%

The probability of confirming the diagnosis of tuberculosis is close to 90% if you send pleural biopsy for histology and one pleural piece for AFB cultures.

Let us consider another issue. What is the value of repetitive pleural biopsy? Malignancy and tuberculosis involve pleura in a scattered fashion. Since the pleural biopsy is done in a blind fashion, it is just a matter of chance whether the biopsy site corresponds to abnormal pleura. You can increase the probability of biopsing the involved site by repetitive biopsy at different sites.

You know the diagnostic yield of first pleural biopsy to be 45%. What do you think is the sensitivity by performing a second pleural biopsy at a different site? In other words, what is the sensitivity of two (sites) pleural biopsies for the diagnosis of malignancy?

The diagnostic sensitivity increases to 60% by a second biopsy. This particular issue was studied by my form boss, Dr. Harold Levine, in 1968. The return decreases after the third attempt.