New Study Shows PenKid's Potential in Kidney Functional Reserve Assessment

HENNIGSDORF, Germany, Oct. 6, 2026 /CourierPR/ -- A new study, published in Physiological Reports, has evaluated Proenkephalin A 119-159 (penKid) for the first time as a marker of kidney functional reserve (KFR). The research, conducted by scientists at the University of New South Wales and Prince of Wales Hospital in Sydney, found that penKid showed a significantly wider dynamic response than cystatin C and creatinine clearance after a protein stimulus.

The study involved 62 participants, including 40 patients undergoing heart surgery and 22 healthy individuals, such as volunteers, kidney donors, and patients who had a kidney auto-transplant. Participants consumed a protein shake, followed by hourly blood sample collection over a five-hour period. Urine samples were also collected for creatinine clearance testing.

PenKid demonstrated a median fractional increase of 44% from baseline, compared to 30% for creatinine clearance and only about 10% for cystatin C. This marked a significant improvement in measuring kidney functional reserve. Unlike creatinine clearance, penKid was able to differentiate between healthy participants and those undergoing heart surgery, indicating a lower KFR in the latter group.

The study also highlighted the practical advantages of penKid. It required no urine collection, minimal fasting, and enabled near real-time assessment of kidney functional reserve from blood samples alone. These features suggest that penKid may offer a fast and simple alternative to assess an individual's kidney functional reserve.

The research builds on previous studies that have shown penKid's ability to detect acute kidney injury (AKI) up to 48 hours before conventional criteria are met. The new Physiological Reports study provides further evidence for penKid's potential as a complementary application in assessing kidney functional reserve, extending its utility beyond acute kidney injury.

The findings could have significant implications for clinical practice, as KFR testing is rarely used due to the cumbersome nature of the reference method, creatinine clearance. By offering a faster, more consistent, and simpler alternative, penKid could help identify subclinical kidney disease and provide a clearer picture of a patient's kidney health.

SphingoTec GmbH, the company behind penKid, is a biomarker company focusing on the out-licensing of innovative critical care solutions for diagnosing, predicting, and monitoring acute medical conditions.