Normal level of PSA in males is:
**Core Concept**
Prostate-Specific Antigen (PSA) is a protein produced by the prostate gland, and its levels can be used as a biomarker for prostate health. The normal level of PSA in males is an important indicator of prostate cancer risk.
**Why the Correct Answer is Right**
The normal level of PSA in males typically ranges from 0 to 4 nanograms per milliliter (ng/mL). This range may vary slightly depending on the laboratory and the individual's age. A PSA level above 4 ng/mL may indicate an increased risk of prostate cancer or other prostate-related issues. The mechanism behind PSA production is complex and involves the interaction of various enzymes and proteins within the prostate gland.
**Why Each Wrong Option is Incorrect**
* **Option A:** 0.1-0.5 ng/mL is too low for the normal range and may indicate a false-negative result.
* **Option B:** 10-20 ng/mL is significantly above the normal range and may indicate an advanced stage of prostate cancer.
* **Option C:** 50-100 ng/mL is an extremely high level of PSA and would likely indicate a severe prostate-related issue, such as metastatic prostate cancer.
**Clinical Pearl / High-Yield Fact**
A PSA level above 4 ng/mL does not necessarily mean that a man has prostate cancer, but it does increase the risk. It's essential to consider other risk factors, such as age, family history, and digital rectal examination (DRE) results, when interpreting PSA levels.
**Correct Answer: C. 4 ng/mL**