HE4, or human epididymis protein 4, is a blood marker most often used alongside CA125 to help evaluate pelvic masses and monitor ovarian cancer. In healthy women, the upper limit of normal generally falls somewhere between about 70 and 90 pmol/L, but the number that counts as “normal” for you depends heavily on your age, whether you have gone through menopause, and even whether you smoke. A result above the reference range does not automatically mean cancer, and a result within range does not guarantee you are cancer-free. Understanding what shifts this number, and what your doctor is actually looking for when they order it, matters more than fixating on any single cutoff.
What HE4 Actually Is
HE4 was originally discovered in the lining of the epididymis (a structure in the male reproductive tract), which is how it got its name. It is a small protein, only 124 amino acids long, belonging to a family of proteins involved in protease inhibition, meaning it helps regulate enzymes that break down other proteins.1PLOS ONE. Human Epididymis Protein-4 (HE-4): A Novel Cross-Class Protease Inhibitor Despite the name, HE4 is produced in many tissues throughout the body, including the respiratory tract and kidneys. It gained clinical attention because ovarian cancer cells produce far more of it than normal tissue does, causing blood levels to rise. Research has also found that HE4 is upregulated in fibrotic kidneys and elevated in the blood of people with kidney fibrosis, hinting at roles well beyond cancer.2PubMed Central. Identification of human epididymis protein-4 as a fibroblast-derived mediator of fibrosis
The Reference Ranges and Why They Vary
If you have ever searched for “normal HE4 levels,” you have probably noticed the numbers are not identical from one source to another. That is because reference limits differ slightly depending on the population studied and the laboratory method used. A large study of healthy women in Poland found an overall upper reference limit of 85 pmol/L, with a premenopausal cutoff of about 73 pmol/L and a postmenopausal cutoff of about 93 pmol/L.3PubMed Central. Human Epididymis Protein 4 (HE4) Reference Limits in Polish Population of Healthy Women, Pregnant Women, and Women with Benign Ovarian Tumors A separate study using a different assay platform reported premenopausal upper limits near 66 pmol/L and postmenopausal limits near 91 pmol/L.4PubMed. The reference intervals for HE4, CA125 and ROMA in healthy female with electrochemiluminescence immunoassay These ranges are broadly consistent but not identical, so the specific cutoff printed on your lab report depends on which assay your laboratory uses and which reference population was used to validate it.
The split between premenopausal and postmenopausal ranges is not arbitrary. A large prospective study of over 2,400 healthy people found that postmenopausal women had a median HE4 of about 36 pmol/L compared to roughly 24 pmol/L in premenopausal women. Among postmenopausal women, HE4 continued to climb with increasing age, while it stayed relatively flat across different ages in women who had not yet reached menopause.5PubMed Central. Age and menopausal status are important factors influencing the serum human epididymis secretory protein 4 level This means a 75-year-old woman’s “normal” HE4 level is genuinely higher than a 55-year-old postmenopausal woman’s, and both are higher than a 35-year-old’s. If your result seems slightly above the printed reference range, your age and menopausal status may explain the difference without anything being wrong.
Smoking, Oral Contraceptives, and Other Lifestyle Factors
One of the most underappreciated influences on HE4 is smoking. In a Nordic reference population study, smokers had HE4 levels roughly 29% higher than nonsmokers, even after adjusting for age and menopausal status.6PubMed Central. Human epididymis protein 4 reference limits and natural variation in a Nordic reference population A separate investigation using serum samples from a biobank confirmed a strong relationship between cotinine levels (a marker of tobacco exposure) and HE4.7International Journal of Gynecological Cancer. HE4 as an Early Detection Biomarker of Epithelial Ovarian Cancer If you smoke and your HE4 comes back mildly elevated, your doctor should weigh that before interpreting the result as suspicious.
Hormonal factors also play a role. Data from a large U.S. national health survey found that women currently using oral contraceptives tended to have lower HE4 levels, while nursing women had slightly higher levels.8PubMed Central. Epidemiologic and biologic correlates of serum HE4 and CA125 in women from the National Health and Nutritional Survey (NHANES) Pregnancy itself can change HE4 levels as well.9PubMed. Human epididymis protein 4: Analysis of national health and nutrition examination survey data None of these shifts are dramatic enough to mimic cancer-level elevations, but they can nudge a result across a borderline cutoff.
Kidney Disease Can Push HE4 Very High
If there is one non-cancer condition that dramatically raises HE4, it is chronic kidney disease (CKD). The kidneys help clear HE4 from the bloodstream, so as kidney function declines, HE4 accumulates. A large retrospective study showed that HE4 climbed steeply as CKD progressed: the median level was about 89 pmol/L in stage 2 CKD, jumped to roughly 211 pmol/L in stage 3, and reached about 787 pmol/L in stages 4 and 5. The correlation between declining kidney filtration rate and rising HE4 was very strong.10PubMed Central. Significantly elevated serum human epididymis protein‐4 in chronic kidney disease patients without ovarian cancer Other research confirmed that even mild decreases in kidney filtration (below 90 mL/min) were enough to raise HE4 above control values.11PubMed. Elevated human epididymis protein 4 concentrations in chronic kidney disease
This is an important practical point. If you have known kidney problems, a high HE4 result is far less meaningful as a cancer indicator. Your doctor will typically check kidney function alongside HE4 to avoid misinterpreting the number. In advanced CKD, HE4 levels can climb to ranges that would look alarming in a person with healthy kidneys, so context matters enormously.
Why HE4 Was Developed Alongside CA125, Not to Replace It
CA125 has been the go-to blood marker for ovarian cancer for decades, but it has a well-known weakness: too many false positives. A long list of benign conditions, including endometriosis, fibroids, and even just having your period, can push CA125 above its cutoff. HE4 was brought into clinical use specifically because it stays normal in many of the situations where CA125 does not. In one study, only about 3% of women with endometriosis had elevated HE4, compared to 67% who had elevated CA125.12PubMed Central. Serum HE4 levels are less frequently elevated than CA125 in women with benign gynecologic disorders A separate study found even starker differences: HE4 was elevated in just 1% of women with benign gynecologic conditions versus 29% for CA125, and HE4 was not elevated at all in patients with cystadenoma or germ cell tumors.13PubMed Central. Serum HE4 is more suitable as a biomarker than CA125 in Chinese women with benign gynecologic disorders
The flip side is that HE4 used alone can miss some cancers that CA125 catches. One study comparing the two markers head to head in Asian women found HE4’s sensitivity was about 57% versus CA125’s 91%, meaning CA125 detected more cancers. But HE4’s specificity was about 97% compared to CA125’s 67%, meaning far fewer false alarms.14PubMed. The use of HE4 in the prediction of ovarian cancer in Asian women with a pelvic mass A study from Nigeria similarly found HE4 outperforming CA125 on specificity and positive predictive value while CA125 edged ahead on sensitivity.15PubMed Central. Comparison of the diagnostic accuracy of HE4 with CA125 and validation of the ROMA index in differentiating malignant and benign epithelial ovarian tumours among patients in Lagos, Nigeria In practical terms, a very high HE4 is a strong signal, but a normal HE4 alone does not rule cancer out. That is why the two markers are usually ordered together.
The ROMA Score and What It Adds
Rather than looking at HE4 or CA125 individually, many clinicians now use the Risk of Ovarian Malignancy Algorithm, or ROMA. This calculation combines your HE4 level, your CA125 level, and your menopausal status into a single risk score. The U.S. Food and Drug Administration has approved ROMA as a tool to help decide whether a woman with a pelvic mass should be referred to a gynecologic oncologist for surgery.16PubMed Central. The emerging role of HE4 in the evaluation of epithelial ovarian and endometrial carcinomas
Multiple studies show ROMA performs better than either marker alone. In a multicenter evaluation, ROMA achieved about 94% sensitivity and 75% specificity overall, with a negative predictive value of 99%, meaning that when ROMA classified a mass as low risk, it was correct almost every time.17PubMed Central. Evaluation of the Diagnostic Accuracy of the Risk of Ovarian Malignancy Algorithm in Women With a Pelvic Mass In one Nigerian study, combining HE4 and CA125 into ROMA pushed specificity and positive predictive value to 100%.15PubMed Central. Comparison of the diagnostic accuracy of HE4 with CA125 and validation of the ROMA index in differentiating malignant and benign epithelial ovarian tumours among patients in Lagos, Nigeria Another study found ROMA had a significantly larger area under the curve than either HE4 or CA125 alone when distinguishing benign gynecologic disease from ovarian cancer.18PubMed Central. HE4 a novel tumour marker for ovarian cancer: comparison with CA 125 and ROMA algorithm in patients with gynaecological diseases
One nuance worth knowing: ROMA’s performance varies by menopausal status. It tends to be very strong in postmenopausal women, where ovarian cancer is most common, and somewhat less specific in premenopausal women.19PubMed Central. Evaluation of HE4, CA-125, Risk of Ovarian Malignancy Algorithm (ROMA) and Risk of Malignancy Index (RMI) in the Preoperative Assessment of Patients with Adnexal Mass In endometriosis specifically, ROMA and HE4 dramatically outperformed CA125: a multicenter study found about 98–99% sensitivity for ROMA and HE4 versus 75% for CA125 at the same specificity.20PubMed Central. HE4 as a serum biomarker for the diagnosis of pelvic masses This is a big deal because endometriosis is extremely common, and CA125 alone frequently triggers unnecessary worry in women who have it.
HE4 Beyond Ovarian Cancer
While ovarian cancer is HE4’s primary clinical application, researchers are investigating it in several other cancers and non-malignant diseases. In endometrial cancer, HE4 is overexpressed in blood and has been linked to poor prognostic features like advanced stage, deeper tumor invasion, and lymph node spread.21PubMed Central. HE4 as a Biomarker for Endometrial Cancer In non-small cell lung cancer, elevated HE4 was independently associated with shorter survival: patients with levels above 140 pmol/L had a median survival of about 18 weeks compared to roughly 46 weeks for those with lower levels.22PLoS ONE. Serum HE4: An Independent Prognostic Factor in Non-Small Cell Lung Cancer
Interestingly, HE4 has also shown up as a potential marker in rheumatoid arthritis, particularly for identifying patients who develop interstitial lung disease (a serious complication involving scarring in the lungs). In one study, about half of rheumatoid arthritis patients had elevated HE4, and those with high levels were far more likely to have lung involvement. An HE4 cutoff of about 104 pmol/L distinguished patients with and without interstitial lung disease with good accuracy.23PubMed Central. Serum Human Epididymis Protein 4 as a Novel Biomarker in Identifying Patients With Interstitial Lung Disease in Rheumatoid Arthritis This fits with HE4’s known connection to fibrosis and tissue remodeling beyond cancer.
Using HE4 to Track Treatment and Watch for Recurrence
For women who have been treated for ovarian cancer, HE4 plays a different role. Instead of diagnosis, the marker becomes a tool for gauging how well treatment is working and catching recurrence early. Research shows that how quickly HE4 drops during chemotherapy correlates with outcomes: women whose HE4 cleared to normal after three cycles of chemotherapy had longer progression-free and overall survival.24PubMed Central. Early clearance of serum HE4 and CA125 in predicting platinum sensitivity and prognosis in epithelial ovarian cancer Elevated HE4 at the time of first relapse also predicted worse outcomes going forward.25PubMed Central. Evaluation of He4 Use in the Diagnosis of Ovarian Cancer: First and Second Recurrence, and an Analysis of HE4 Concentration during Second- and Third-Line Chemotherapy
Multiple research groups have found that high preoperative HE4 is an independent predictor of worse overall survival in ovarian cancer, with one early report estimating roughly twice the risk of death compared to patients with lower levels. Combining HE4 with CA125 appears to strengthen this prognostic signal further.26Archives of Cancer Biology and Therapy. Prognostic Role of Human Epididymis Protein 4 (HE4) in Ovarian Cancer Treatment: Our Point of View For patients in follow-up after treatment, a rising HE4 on serial blood draws can be an early warning that cancer is returning, sometimes before imaging picks it up.
Why the Same HE4 Level Can Mean Different Things on Different Lab Machines
One frustration for patients and doctors alike is that HE4 results are not perfectly interchangeable between laboratories. Different commercial assays use different antibodies to detect HE4, and those antibodies bind to different parts of the protein with different affinities. A direct comparison of two widely used HE4 assays found that they did not always agree, partly because one targets the protein’s front end while the other targets its back end.27PubMed Central. Comparison of two immunoassays for the measurement of serum HE4 for ovarian cancer This means a value of 80 pmol/L on one platform might read as 70 or 90 on another, and the reference cutoff printed on the report should match the specific assay used.
How samples are handled before analysis also matters. Pre-analytical conditions like how long the blood sits before being processed and at what temperature can shift results for tumor markers including HE4.28PubMed. Pre-analytical stability of the CEA, CYFRA 21.1, NSE, CA125 and HE4 tumor markers The practical takeaway: if you are having HE4 tracked over time, try to have it drawn at the same lab using the same assay each time. Comparing numbers from different laboratories can create the illusion of a trend that does not actually exist.
When Adding HE4 and ROMA May Not Be Worth It
Despite HE4’s strengths, there is a legitimate debate about when it adds enough clinical value to justify the cost. A prospective study comparing different triage strategies for women with pelvic masses found that adding biomarkers like HE4 and ROMA to expert ultrasound assessment did not improve diagnostic accuracy in premenopausal women and was more expensive. In postmenopausal women the story was similar: no diagnostic advantage was found over skilled ultrasound evaluation alone.29PubMed. Diagnostic accuracy and cost-effectiveness of different strategies to triage women with adnexal masses This does not mean HE4 is useless — it means that in centers where expert ultrasound is available, adding blood markers may not change the clinical decision. In settings without that ultrasound expertise, HE4 and ROMA fill a more critical gap.
What HE4 Is Doing Inside Cancer Cells
For those curious about why cancer cells bother producing so much HE4, the answer is that the protein appears to actively help tumors grow and spread. Lab experiments have shown that ovarian cancer cells engineered to overexpress HE4 proliferate faster, invade surrounding tissue more aggressively, and metastasize more readily.30PubMed Central. Overexpression of HE4 (human epididymis protein 4) enhances proliferation, invasion and metastasis of ovarian cancer Conversely, when researchers silenced HE4 in cancer cell lines, cell adhesion, migration, and tumor growth all slowed down. The mechanism appears to involve signaling pathways that control cell growth and movement.31PubMed. Human epididymis protein 4 (HE4) plays a key role in ovarian cancer cell adhesion and motility There is also evidence that high HE4 expression, in combination with certain sugar molecules on the cell surface, activates stress-response pathways that help tumors resist chemotherapy.32PubMed. Human Epididymis Protein 4 and Lewis y Enhance Chemotherapeutic Resistance in Epithelial Ovarian Cancer Through the p38 MAPK Pathway This dual role — both a biomarker in the blood and a functional driver of tumor behavior — makes HE4 an attractive target for future therapies, not just a passive number on a lab report.
Practical Tips for Making Sense of Your Results
If you are staring at an HE4 result and trying to figure out what it means, a few guidelines can help. First, check which reference range your lab uses, and note whether it is split by menopausal status. An HE4 of 80 pmol/L in a premenopausal woman is meaningfully different from the same number in a postmenopausal woman, even though the absolute value is identical. Second, if you smoke, expect your HE4 to run higher than average. A mildly elevated result in a smoker is much less alarming than the same number in a nonsmoker. Third, kidney function needs to be on the table. Even moderate kidney impairment can double or triple HE4 levels without any cancer present.
If your doctor ordered HE4 because of a pelvic mass, the result is almost certainly being interpreted alongside CA125, ultrasound findings, and possibly a ROMA calculation — not in isolation. A low ROMA score paired with reassuring imaging is strongly predictive that a mass is benign. A high ROMA or a markedly elevated HE4 (well above the reference range in someone with normal kidneys who does not smoke) warrants further evaluation, usually with referral to a gynecologic oncologist.
Finally, for serial monitoring after ovarian cancer treatment, the trend matters more than any single value. A steadily rising HE4 across multiple blood draws is more concerning than a single elevated reading, which could reflect lab variability, a recent illness, or temporary changes in kidney function. Your oncologist will typically track the trajectory over several measurements before making clinical decisions based on HE4 alone.