Evaluation of Automated Determination of Bilirubin and Oxyhemoglobin in Cerebrospinal Fluid Using the DrugLog© Instrument.

Abstract

In a heterogenous group of patients with acute headache it is important to diagnose subarachnoid hemorrhage (SAH), a potentially lethal but treatable condition, with short turnaround time and high precision. Spectrophotometry of cerebrospinal fluid (CSF) is an essential part in the investigation of patients with suspected SAH but the analysis is slow and operator dependent. We have evaluated a new instrument for ultraviolet and visible light (UV-VIS) spectroscopy (DrugLog©, Pharmacolog, Uppsala, Sweden) for automatic determination of oxyhemoglobin and bilirubin in CSF samples. The instrument incorporates software for calculating the absorbance values thus eliminating operator bias. Bilirubin and oxyhemoglobin in CSF was analyzed both with DrugLog© and traditional spectrophotometry at 415 and 476 nanometers (A415 and A476) using patient samples containing varying amounts of bilirubin and oxyhemoglobin. The DrugLog© method showed a strong correlation both for bilirubin (Pearson's r = 0.996) and oxyhemo-globin (Pearson's r = 0.993). The DrugLog© method had good linearity and precision, offering an automated determination of bilirubin and oxyhemoglobin, eliminating operator bias. The DrugLog© instrument has a short assay time and showed good agreement with traditional spectrophotometry.