How concerned should I be about being inconsistent on this

According to the National Comprehensive Cancer Network (NCCN) Guidelines for Prostate Cancer Monitoring, consistency in PSA testing is important for several reasons:

1. Same Laboratory: The NCCN recommends using the same laboratory for PSA tests whenever possible, as different labs may use different testing methods that can vary by 20-30% in their results.

2. Time of Day: The American Urological Association (AUA) guidelines note that PSA levels can naturally fluctuate throughout the day. They recommend getting your PSA test at a similar time of day for each test, preferably in the morning.

However, the American Cancer Society provides reassuring context: Small inconsistencies in timing or occasional use of different labs are not usually cause for major concern. What's most important is the overall trend in PSA levels over time, not single measurements.

Key recommendations from these sources:

• Try to maintain consistency when possible
• Keep records of which labs you use
• Note any factors that might affect results (like infections or recent procedures)
• Don't panic about occasional inconsistencies
• Focus on long-term trends rather than individual readings

Most importantly, discuss any concerns about PSA testing with your healthcare team, as they can best interpret your specific situation and results.

Would you like me to provide more specific information about any of these aspects of PSA testing?