Final answer:
The statement regarding codes for diseases classified elsewhere not being used as first-listed or principal diagnosis codes is misleading - these codes may accompany but do not replace principal diagnosis codes. ICD codes can commonly be found in medical laboratories and health-care management systems.
Step-by-step explanation:
The statement 'In diseases classified elsewhere, are codes never permitted to be used as first listed or principal diagnosis codes' can be misleading. In the context of ICD codes, there are specific instances where a code that points to a condition classified elsewhere is used to support the principal diagnosis without being the first-listed code. These are typically supplementary codes that denote an underlying condition or provide additional information about the illness affecting the patient. The principal diagnosis code is used to describe the main condition or reason for the medical encounter. Codes that are classified elsewhere serve to provide detail but don't replace primary diagnosis codes.
Regarding where you might find an ICD code, locations would include medical laboratories and the health-care management system. In medical laboratories, ICD codes are used to identify necessary tests to confirm the diagnosis. Meanwhile, in the health-care management system, these codes verify whether treatments and laboratory work are appropriate for the patient's condition.