AbstrakPendahuluan Studi ini untuk mengetahui hubungan kadar Glial Fibrillary Acidic Protein (GFAP) serumdengan tingkat keparahan penderita cedera kepala.Metode Penelitian ini merupakan studi analitik yang menggunakan desain cross sectional. Penelitian iniberlangsung dari Juni 2013 sampai Maret 2014 di RSUP H. Adam Malik. Pasien cedera kepala beratdan sedang dilibatkan dalam penelitian ini jika onset kurang dari 48 jam. Pasien yang dipilih dievaluasiberdasarkan pada temuan Computed Tomography (CT) scan kepala. Pasien diambil dengan caraconsecutive sampling, kemudian dilakukan pengambilan sampel darah untuk pemeriksaan GFAP dandilakukan pemeriksaan GFAP serum kumulatif.Hasil Kadar GFAP berhubungan signifikan dengan Glasgow Coma Scale (GCS) setelah resusitasi (r=-0.631, p=0.0001). Korelasi yang terjadi merupakan korelasi negatif(r=-0,631, p=0,0001). Jika GCSsetelah resusitasi semakin tinggi, kadar GFAP serum akan semakin rendah.Simpulan Kadar GFAP penderita cedera kepala berat (11,9±10,52) lebih tinggi secara signifikandibandingkan penderita cedera kepala sedang (1.82±1.60, p=0.0001). Terdapat korelasi yang signifikanantara kadar GFAP serum dengan GCS awal setelah resusitasi (r=-0.631; p=0.0001).Kata Kunci GFAP, Cedera kepala, biomarkerAbstractIntroduction This study was to determine the relationship of serum Glial Fibrillary Acidic Protein (GFAP)l evels with severity of head injury patients.Methods This study was an analytical study using cross-sectional design. The study lasted from June2013 until March 2014 at Adam Malik General Hospital. Severe head injury patients were included in thestudy if the onset is less than 48 hours. Selected patients were evaluated based on the findings of the Computed Tomography (CT) scan of the head. Consecutive sampling was done to select the subjects,then blood samples were taken for examination and imeasurement of cumulative GFAP serum level.Results The results showed that GFAP levels were associated significantly with GCS after resuscitation(r = -0.631, p = 0.0001). The correlation was a negative correlation (r = -0.631, p = 0.0001). If the higherGlasgow Coma Scale (GCS) after resuscitation, serum GFAP levels would be even lower.Conclusion Levels of GFAP severe head injury patients (11.9 ± 10.52) was significantly highercompared to patients with moderate head injury (1.82 ± 1.60, p = 0.0001). There is a significantcorrelation between serum GFAP levels with initial GCS after resuscitation (r = -0.631, p = 0.0001).Keywords : GFAP, head injury, biomarker