Bilirubinometers

Bilirubinometers are medical devices used to measure bilirubin, a yellow pigment produced during heme breakdown. They are primarily employed to assess jaundice and to screen for hyperbilirubinemia, especially in newborns, where timely detection can guide further testing and treatment.

There are two main types. Transcutaneous bilirubinometers (TcB) are noninvasive devices that estimate total serum bilirubin by measuring skin reflectance at sites such as the forehead or sternum. They rely on calibration algorithms to convert reflectance data into bilirubin values and are commonly used for rapid screening in clinics and neonatal units. Blood-based bilirubinometers, used in laboratories or point-of-care settings, analyze serum or plasma samples (often via spectrophotometry or colorimetric methods) to determine total and, in some systems, direct (conjugated) bilirubin.

Operation principles vary by type. TcB devices typically use light in the blue-green spectrum to capture skin reflectance and apply an algorithm to estimate bilirubin concentration. Laboratory bilirubinometers measure enzymatic or chemical reactions or absorbance changes to quantify bilirubin concentration. Results are reported in mg/dL (or μmol/L).

Clinical use and limitations. TcB readings provide rapid, noninvasive screening but can be influenced by skin pigmentation, age in hours, gestational age, phototherapy exposure, and device calibration. They generally serve as an aid to decide whether a blood test is needed rather than a definitive diagnosis. Serum bilirubin measurements remain the standard for accuracy, particularly when bilirubin levels are high or there is concern for conjugated hyperbilirubinemia.

See also: neonatal jaundice, bilirubin, phototherapy, Jendrassik-Grof method.