Final answer:
The definitive test to establish a diagnosis of osteomalacia is a bone biopsy. Other diagnostic tools such as bone mineral density screening or serum alkaline phosphate levels may be relevant for conditions like osteoporosis or Paget's disease, but they are not the primary tools for osteomalacia diagnosis.
Step-by-step explanation:
A test to ultimately establish the diagnosis of osteomalacia is bone biopsy (Option E). Osteomalacia is characterized by softening of the bones due to the faulty calcification that occurs when bone formation does not properly mineralize. In contrast, disorders like Paget’s disease and osteoporosis have different markers and diagnostic criteria.
For instance, Paget's disease features elevated blood levels of alkaline phosphatase, a key indicator that differs from osteomalacia. Osteoporosis is often assessed through bone mineral density screening such as Dual-energy X-ray absorptiometry (DEXA), whereas osteomalacia requires a bone biopsy for a definitive diagnosis.
While options like positron emission tomography, bone mineral density screening, and nuclear bone scan are valuable in evaluating other bone conditions, they are not the primary tools for diagnosing osteomalacia. Elevated serum alkaline phosphate could suggest Paget's disease rather than osteomalacia since alkaline phosphatase is typically not elevated in osteomalacia as it is in Paget's.