PERBEDAAN NILAI KLIRENS COCKCROFT-GAULT BERDASAR HASIL PEMERIKSAAN KREATININ METODA JAFFE UNCOMPENSATED, RATE-BLANKED COMPENSATED DENGAN ENZIMATIK

Abstract

Backgrounds: Cockroft-Gault clearance value depends on the results of serum creatinine examination based on creatinine examination method used. Uncompensated Jaffe method based on pikrat alkaline reaction that is widely used by clinical laboratories in Indonesia is very susceptible to interference substances Rate-blanked compensated Jaffe method is a modification of Jaffe method with the purpose to reduce interference substance. Enzymatic method is very specific because it is not influenced by non creatinine chromogen. Purpose: To prove the difference in Cockcroft-Gault clearance values based on the results of serum creatinine examination using uncompensated Jaffe method, rate-blanked compensated Jaffe method, and enzymatic method. Materials and Methods: Calculation of Cockcroft-Gault clearance values was performed based on the results of serum creatinine examination using uncompensated Jaffe method, rate-blanked compensated Jaffe method, and enzymatic method on 30 samples from males and females of 18 to 30 years old with BM1 20 to 25, that were non-vegetarian, no history of diabetes, not using drug or supplement within 24 hours before blood sampling, no pregnancy, no amputation, no edema, no previous history of kidney disease, serum creatinine was within the limits of reference values, fasting of at least 8 hours and agreement to participate in the study. The exclusion criteria were if the serum was hemolitic, lipemic or icteric. Serum creatinine examination was performed using autoanalyzer according to the manufacture's instructions. Statistical test was performed using unpaired t test and Mann-Whitney test. Results: The mean result of serum creatinine examination using uncompensated Jaffe method was 0.83 ± 0.20 mg/dL, rate-blanked compensated Jaffe method was 0.82 ± 0.18 mg/dL, and enzymatic method was 0.83 ± 0.18 mg/dL. The mean value of Cockcroft-Gault clearance based on the result of serum creatinine examination using uncompensated Jaffe method was 113.84 ± 25.24 mL/minute, rate-blanked compensated Jaffe method was 113.43 ± 18.05 mL/minutes, and enzymatic method was 112.68 ± 17.46 mL/minute. In the result of unpaired t test we found differences in the result of serum creatinine examination using both uncompensated Jaffe method and rate-blanked compensated Jaffe method as compared with enzymatic method (p = 0.004 and p = 0.0001). In the result of Mann-Whitney test we found differences in Cockcroft-Gault clearance value based on the result of serum creatinine examination using both uncompensated Jaffe method and rate-blanked compensated Jaffe method as compared with enzymatic method (p = 0.001 and p = 0.0001). Conclusion: There are differences in Cockcroft-Gault clearance value based on serum creatinine examination method used. The Jaffe method is susceptible to interference substance, and modification of the Jaffe method has not yet eliminated the susceptibility of the method to interference. Suggestion: The calculation of Cockcroft-Gault clearance should use the result of serum creatinine examination using enzymatic method. Latar belakang : Nilai klirens Cockcroft-Gault bergantung pada hasil pemeriksaan kreatinin serum berdasar metoda pemeriksaan kreatinin yang digunakan. Metoda Jaffe uncompensated berdasar reaksi pikrat alkalin yang banyak digunakan laboratorium klinik di Indonesia sangat rentan terhadap substansi interferensi (kromogen non kreatinin). Metoda Jaffe rate-blanked compensated merupakan modifikasi metoda Jaffe untuk mengurangi substansi interferensi. Metoda enzimatik sangat spesifik karena tidak terpengaruh kromogen non kreatinin. Tujuan : Membuktikan perbedaan nilai klirens Cockcroft-Gault berdasar hasil pemeriksaan kreatinin serum metoda Jaffe uncompensated, Jaffe rate-blanked compensated dengan enzimatik. Bahan dan Metoda : Dilakukan perhitungan nilai klirens Cockcroft-Gault berdasar hasil penieriksaan kreatinin serum metoda Jaffe uncompensated, Jaffe rate-blanked compensated dengan enzimatik pada 30 sampel pria dan wanita berusia 18 s/d 30 tahun dengan BMI 20 s/d 25, tidak vegetarian, tidak ada riwayat diabetes, tidak minum obat-obatan dan suplemen dalam jangka 24 jam sebelum sampling darah, tidak hamil, tidak amputasi, tidak edema, tidak ada riwayat penyakit ginjal sebelumnya, kreatinin serum dalam batas nilai rujukan, punga minimal 8 jam dan bersedia berpartisipasi dalam penelitian. Kriteria eksklusi ialah apabila serum hemolitik, lipemik atau ikterik. Pemeriksaan kreatinin serum secara otomatik menggunakan autoanalizer berdasar prosedur kerja masing-masing metoda. Uji statistik menggunakan uji t tidak berpasangan dan uji Mann-Whitney. Hasil : Rerata hasil pemeriksaan kreatinin serum metoda Jaffe uncompensated 0,83± 0,20 mg/dl, metoda Jaffe rate-blanked compensated 0,82 ± 0,18 mg/dl, metoda enzimatik 0,83 ± 0,18 mg/cll. Rerata nilai klirens Cockcroft Gault berdasar hasil pemeriksaan kreatinin serum metoda Jaffe Uncompensated ialah 113,84 ± 25,24 mL/menit, metoda Jaffe rate-blanked compensated 113,43 ± 18,05 mL/menit dan metoda enzimatik 112,68± 17,46 mL/menit. Hasil uji t tidak berpasangan didapatkan perbedaan hasil pemeriksaan kreatinin serum metoda Jaffe uncompensated maupun metoda Jaffe rate-blanked compensated dibanding metoda enzimatilc ( p=0,004 dan p=0,0001). Hasil uji Mann-Whitney didapatkan perbedaan nilai klirens Cockcroft Gault berdasar hasil pemeriksaan kreatinin serum metoda Jaffe Uncompensated maupun metoda Jaffe rate-blanked compensated dibanding metoda enzimatik ( p=0,0001 dan p=0,0001) Kesimpulan : Terdapat perbedaan nilai klirens Cockcroft-Gault berdasar metoda pemeriksaan kreatinin serum yang digunakan. Metoda Jaffe rentan terhadap substansi interferensi dan modifikasi metoda Jaffe belum dapat merighilangkan kerentanan metoda tersebut terhadap interferensi. Saran : Perhitungan klirens Cockroft-Gault sebaiknya menggunakan hasil pemeriksaan kreatinin serum metoda enzimatik