Final answer:
Preexamination variables in the medical field can affect the integrity of specimens and alter test results. Fasting compliance is crucial for accurate results, patients should lie down before aldosterone tests, short-term exercise can affect test results, and higher altitudes impact oxygen and hemoglobin levels.
Step-by-step explanation:
Preexamination variables are factors that can affect the integrity of specimens and alter test results in the medical field. One correct statement regarding preexamination variables is that if a patient has not complied with fasting requirements, the venipuncture should be cancelled, as it can affect the accuracy of the results. This is especially important for tests that require fasting, such as glucose or lipid panel tests.
Another correct statement is that patients should lie down for 30 minutes before drawing blood for aldosterone tests. This position allows for better regulation of bodily fluids and can ensure more accurate test results.
Contrary to option (C), short-term exercise can indeed affect test results. Vigorous exercise before a blood test can alter certain values, such as increased levels of creatine kinase or lactate dehydrogenase.
Finally, option (D) is correct as well. At higher altitudes, oxygen levels are lower, which ultimately impacts the amount of hemoglobin that can bind to oxygen in the blood.
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