Evaluation of Reference Intervals of Some Selected Chemistry Parameters using Bootstrap Technique in Dogs

Bootstrap 기법을 이용한 개의 혈청검사 일부 항목의 참고범위 평가

  • Kim, Eu-Tteum (School of Veterinary Medicine and Institute of Veterinary Science, Kangwon National University) ;
  • Pak, Son-Il (School of Veterinary Medicine and Institute of Veterinary Science, Kangwon National University)
  • 김으뜸 (강원대학교 수의학부대학 임상병리학교실) ;
  • 박선일 (강원대학교 수의학부대학 임상병리학교실)
  • Published : 2007.12.31

Abstract

Parametric and nonparametric coupled with bootstrap simulation technique were used to reevaluate previously defined reference intervals of serum chemistry parameters. A population-based study was performed in 100 clinically healthy dogs that were retrieved from the medical records of Kangwon National University Animal Hospital during 2005-2006. Data were from 52 males and 48 females(1 to 8 years old, 2.2-5.8 kg of body weight). Chemistry parameters examined were blood urea nitrogen(BUN)(mg/dl), cholesterol(mg/dl), calcium(mg/dl), aspartate aminotransferase(AST)(U/L), alanine aminotransferase(ALT)(U/L), alkaline phosphatase(ALP)(U/L), and total protein(g/dl), and were measured by Ektachem DT 60 analyzer(Johnson & Johnson). All but calcium were highly skewed distributions. Outliers were commonly identified particularly in enzyme parameters, ranging 5-9% of the samples and the remaining were only 1-2%. Regardless of distribution type of each analyte, nonparametric methods showed better estimates for use in clinical chemistry compare to parametric methods. The mean and reference intervals estimated by nonparametric bootstrap methods of BUN, cholesterol, calcium, AST, ALT, ALP, and total protein were 14.7(7.0-24.2), 227.3(120.7-480.8), 10.9(8.1-12.5), 25.4(11.8-66.6), 25.5(11.7-68.9), 87.7(31.1-240.8), and 6.8(5.6-8.2), respectively. This study indicates that bootstrap methods could be a useful statistical method to establish population-based reference intervals of serum chemistry parameters, as it is often the case that many laboratory values do not confirm to a normal distribution. In addition, the results emphasize on the confidence intervals of the analytical parameters showing distribution-related variations.

혈청검사항목의 해석기준으로 사용하는 참고범위는 측정 장비와 병원마다 차이를 보이기 때문에 병원 간 정보를 교환하고 해석하는데 어려움이 많다. 또한 동일한 병원에서도 내원한 환자의 특성을 고려하여 참고범위를 재설정하는 것이 일반모집단의 특성을 제대로 반영한다. 본 연구에서는 강원대학교 수의학부대학 동물병원에서 설정한 혈청화학 검사 항목의 참고범위를 재평가하기 위하여 2005-2006년 동안 본원에 내원한 임상적으로 건강한 개 100두(1-8세, 체중 2.2-5.8 kg)의 혈청검사 일부 항목을 모수 및 비모수적 bootstrap 모의시험으로 분석하였다. 평가항목은 BUN(mg/dl), cholesterol(mg/dl), calcium(mg/dl), aspartate aminotransferase(AST, U/L), alanine aminotransferase(ALT, U/L), alkaline phosphatase(ALP, U/L) 및 total protein(g/dl)으로 Ektachem DT 60 분석기(Johnson & Johnson)로 측정하였다. 칼슘을 제외한 모든 항목이 왜곡이 매우 심한 분포를 보였으며 특히 혈청 효소항목의 outlier는 전체 자료의 5-9%, 기타 항목은 1-2%를 보였다. 각 항목의 분포에 상관없이 모수적 방법에 비하여 비모수적 방법으로 추정한 참고범위가 임상적으로 유용하였으며 추정된 참고범위는 BUN 14.7(7.0-24.2), cholesterol 227.3(120.7-480.8), calcium 10.9(8.1-12.5), AST 25.4(11.8-66.6), ALT 25.5(11.7-68.9), ALP 87.7(31.1-240.8), and total protein 6.8(5.6-8.2)로 나타났다. 이러한 결과는 모집단의 특성을 고려하여 참고범위를 재설정하는데 비모수적 모의시험이 매우 유용하며 특히 측정항목의 분포에 무관하게 사용할 수 있는 장점이 있는 것으로 사료된다.

Keywords

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