Interpretation of bronchoalveolar lavage fluid cytology - ILD care

Interpretation of BALF cytology
numerous iron-laden macrophages points to causes of disorders associated with DAD. Additional iron staining
may be helpful to distinguish disorders with DAD form other ILD, e.g. pulmonary vascular disorders such as M.
Wegener from sarcoidosis as both may present with a lymphocytosis in BALF [26]. Moreover, the value of BALF
cytology findings for the diagnosis of non-infectious conditions in ICU patients with suspected pneumonia was
demonstrated [7]. The medical history is extremely important to identify the possible cause of the pulmonary
damage in those cases. In line with this, one should always interpreted the BALF data in the context of other
relevant information such as the occupational history of the patient, as well as other clinical parameters, such as
the presence of precipitines, an elevated serum ACE level, HRCT features etc. Therefore, we want to emphasize the
importance of careful assessment of the all cytological BALF characteristics in order to improve the diagnostic
accuracy in patients with diffuse lung damage. The computer model should be used with caution considering the
limited number of diseases included in the model. However, the included ILD i.e. sarcoidosis, IPF and EAA cover
for about 80-90 percent of all ILD.
This study only focussed on BALF data obtained in the diagnostic work-up of patients suffering from diffuse lung
diseases. Although the accuracy of high resolution computed tomography (HRCT) in the differential diagnosis of
these patients has been widely appreciated [1,2,27-29], no HRCT data were included in this model. It would be very
helpful if a HRCT score could be used to classify a certain disorder. However, the attempts made to evaluate the
usefulness of HRCT in characterize disease were mainly descriptive [27]. Moreover, the appearances on HRCT
were correlated with disease activity in fibrosing alveolitis [29-31], acute farmer’s lung [32], sarcoidosis [33, 34] and
Wegener’s granulomatosis [26]. It would be of great interest to develop a valuable diagnostic quantitative HRCT
score which discriminates between certain ILD. Additionally, a prospective study should address the effect of
including this score in a logistic regression model upon the diagnostic probabilities of the BALF data presented in
this study. Including more clinical data in the model may further improve the diagnostic accuracy of patients
suffering from diffuse lung diseases.
In conclusion, when applied according to standardized protocols, and considered in the context of other
information from conventional ancillary diagnostic tests, such as a HRCT scan, BAL appears to be useful in
the diagnosis of diffuse lung diseases. The updated computer program provides a reliable prediction of the
diagnosis of a bacterial pneumonia or one of the three most frequent interstitial lung diseases, and is thought
to improve the diagnostic power of BALF analysis in conjunction with other important diagnostic procedures.
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