There are many types of cancer screening methods available — but what exactly sets them apart? Can any test tell you with 100% certainty whether you have cancer?
Let’s take a closer look at two major types of blood-based cancer screening: Cancer Marker Tests and mRNA Testing. The first helps with preliminary risk assessment, while the second focuses on ultra-early detection.
They differ in principle, accuracy, and target users — and combining both can improve overall screening results.

What is a cancer marker test?

A cancer marker test measures the concentration of specific proteins or antigens produced by cancer cells or the body’s response to them — for example:

• AFP (liver cancer)

• CEA (colorectal cancer)

• CA125 (ovarian cancer)

These tests are mainly used for preliminary risk assessment, monitoring treatment effectiveness, and detecting recurrence.
However, the results can easily be affected by inflammation, smoking, or other health conditions, leading to false positives or false negatives. Their sensitivity is limited — in early-stage cancer, only about 5–30% of cases show elevated levels.

What is mRNA testing?

mRNA testing (circulating tumor cell screening) uses dynamic gene detection technology to analyze tumor-related mRNA molecules released into the blood.
Each gram of tumor tissue can release millions of cells daily, which can be captured and analyzed. This allows detection of tumors as small as 0.2 cm, with an accuracy rate of 93–97%.

What is ctDNA Testing?

ctDNA testing uses next-generation sequencing (NGS) and AI to analyze tumor DNA fragments in the blood, detecting mutation signals as low as 0.25%. This makes it suitable for early screening and MRD (minimal residual disease) monitoring, with accuracy of 92-99%, and generally stronger than mRNA for recurrence monitoring and precision therapy.

What cancers can mRNA /ctDNA testing detect?

mRNA testing enables earlier detection than cancer markers, screening for cancers like lung, liver, stomach, pancreatic, colorectal, nasopharyngeal, and breast cancer, with benefits of no radiation and non-invasiveness.

ctDNA offers non-invasive testing, detecting even more cancer types than mRNA, aided by AI for the highest specificity among the three methods.

Thus, mRNA/ctDNA testing outperforms traditional imaging (like CT, which needs 1cm+ tumors) for ultra-early screening.

A quick comparison at a glance

Who should take which test?

• Cancer marker test: Recommended for adults over 40, individuals with a family history of cancer or chronic conditions, and existing cancer patients for tracking trends. Suggested 1–2 times per year.

• mRNA/ ctDNA test: Ideal for high-risk individuals (e.g., smokers, drinkers, those with family cancer history) or health-conscious individuals for annual screening, as well as postoperative monitoring. Suggested every 6–12 months.

• Healthy people without symptoms: Start with cancer marker testing. If results appear abnormal, follow up with other screenings.

Human Health offers several cancer risk assessment programs available on its online store, including:

• SPOT-MAS Women 10 Types Multi-Cancer Early Detection (HCDNA01): HK$3,860 (original HK$9,650) 

• SPOT-MAS Men 8 Types Multi-Cancer Early Detection (HCDNA02): HK$3,160 (original HK$7,900)

All plans are available for online purchase through the Human Health eShop .
If you have any questions about these packages, please contact our hotline at 2397 2111 for assistance.

If you have any concerns, consult your doctor. Abnormal results usually require further imaging or clinical assessment, as no single test alone can confirm a cancer diagnosis.