what specimens are required to diagnose respiratory disease?

there are several things that are done.
Chest xrays, broncoscopy (spelling?)which is done under anesthesia in
an outpatient center or hospital, CT scans - that's what comes to mind
right now. Neither of the tests are painful.

My mom died of lung disease (cancer from 25 years of smoking a few
packs a day) and another friend of mine has respiratory problems and
is being managed veyr well by a Pulmonary specialist.  So I am
familiar with some of the protocols.

If you or whoever you are writing for has a HMO or PPO managed care
plan, you can easily locate an excellent Pulmonary specialist.  Also
contact the hospital of your choice & ask for their REferral
Department. They can also give you some names and inform you of the
plans the doctor belongs to.

Good luck.

The types of tests ordered or the specimens collected depend on what
type of respiratory disease is suspected. If an infection is
suspected, cultures can be run either on sputum, on tissue obtained
during a brochoscopy, or on what are called "bronchial washings." This
is where the pulmonologist, during the bronchoscopy, flushes a small
amount of saline solution into the lungs, and then immediately sucks
it back out. This fluid now contains cells, bacteria, etc., which can
be analyzed in the laboratory. If malignancy is suspected, then either
tissue samples obtained via biopsy or cells from bronchial washings
are needed to prove it is cancer. Respiratory consitions such as
asthma or COPD do not require specimens for diagnosis, but rely on
pulmonary function tests that measure the lungs' functional capacity.