| NSA | Neurological Society of America; normal serum albumin; no salt added; no significant abnormality; no... |
|---|---|
| OAA | Old Age Assistance; Older Americans Act; Opticians Association of America; oxaloacetic acid |
| OSA | obstructive sleep apnea; Office of Services to the Aging; Optical Society of America; ovarian sectio... |
| PCA | para-chloramphetamine; parietal cell antibody; passive cutaneous anaphylaxis; patient care assistant... |
| PIA | photoelectric intravenous angiography; plasma insulin activity; preinfarction angina; Psychiatric In... |