<![CDATA[Electrolyte examination is performed to assess the levels of the major electrolytes in the blood. This examination is used to help establish the diagnosis of fluid balance disorders and acid-base imbalances in the body. The test materials commonly used for electrolyte examination are serum and heparinized plasma. Differences in the type of test material may affect the results of electrolyte examinations. This study aimed to determine the differences in electrolyte levels, including sodium, potassium, chloride, and ionized calcium, between serum and heparinized plasma test materials. This study employed a quantitative approach with an analytical observational design and a cross-sectional design. A total of 15 samples were obtained from patients undergoing electrolyte examinations at Muhammadiyah Babat General Hospital in February 2026. Electrolyte examinations were performed using the Erba Electrolyte Analyzer with the direct Ion-Selective Electrode (ISE) method. The results showed that the mean sodium levels were 139.29 mmol/L in serum and 136.49 mmol/L in heparinized plasma, the mean potassium levels were 3.79 mmol/L in serum and 3.58 mmol/L in heparinized plasma, the mean chloride levels were 106.77 mmol/L in serum and 105.63 mmol/L in heparinized plasma, and the mean ionized calcium levels were 1.00 mmol/L in serum and 0.89 mmol/L in heparinized plasma. The examination results were analyzed using the paired t-test and the Wilcoxon signed-rank test according to the data distribution. The results showed significant differences in sodium, potassium, and ionized calcium levels between serum and heparinized plasma test materials, with significance values of p < 0.05. Meanwhile, chloride levels showed no significant difference between serum and heparinized plasma test materials, with a significance value of p > 0.05. Based on the data analysis that had been conducted, significant differences were found in sodium, potassium, and ionized calcium levels between serum and heparinized plasma test materials, whereas chloride levels showed no significant difference. ABSTRAK Pemeriksaan elektrolit merupakan pemeriksaan untuk menilai kadar elektrolit utama di dalam darah. Pemeriksaan ini digunakan untuk membantu menegakkan diagnosis adanya gangguan keseimbangan cairan maupun ketidakseimbangan asam-basa dalam tubuh. Bahan uji yang umum digunakan pada pemeriksaan elektrolit adalah serum dan plasma heparin. Perbedaan jenis bahan uji dapat memengaruhi hasil pemeriksaan elektrolit. Penelitian ini dilakukan untuk mengetahui adanya perbedaan kadar elektrrolit, meliputi kadar natrium, kalium, klorida, dan kalsium terionisasi antara bahan uji serum dengan bahan uji plasma heparin. Penelitian ini menggunakan pendekatan kuantitatif observasional analitik dengan desain cross-sectional. Jumlah sampel sebanyak 15 sampel dari pasien yang menjalani pemeriksaan elektrolit di RSU Muhammadiyah Babat pada bulan Februari 2026. Pemeriksaan elektrolit dilakukan menggunakan alat Erba Electrolyte Analyzer dengan metode Ion Selective Electrode (ISE) secara langsung. Hasil pemeriksaan menunjukkan bahwa rerata kadar natrium pada serum sebesar 139,29 mmol/L dan plasma heparin sebesar 136,49 mmol/L, kadar kalium pada serum sebesar 3,79 mmol/L dan plasma heparin sebesar 3,58 mmol/L, kadar klorida pada serum sebesar 106,77 mmol/L dan plasma heparin sebesar 105,63 mmol/L, serta kadar kalsium terionisasi pada serum sebesar 1,00 mmol/L dan plasma heparin sebesar 0,89 mmol/L. Data hasil dari pemeriksaan elektrolit akan dianalisa menggunakan uji T-dependen dan uji Wilcoxon sesuai dengan distribusi data. Hasil uji pada kadar natrium, kalium, dan kalsium terionisasi antara bahan uji serum dengan bahan uji plasma heparin menunjukkan adanya perbedaan bermakna, dengan nilai signifikansi (p < 0,05). Sedangkan, pada kadar klorida tidak terdapat perbedaan bermakna antara bahan uji serum dan bahan uji plasma heparin dengan nilai signifikansi (p > 0,05). Berdasarkan analisis data yang telah dilakukan, ditemukan perbedaan yang bermakna pada kadar natrium, kalium, dan kalsium terionisasi antara bahan uji serum dengan plasma heparin, sedangkan kadar klorida tidak menunjukkan perbedaan bermakna.]]>
