BUN、肌酐、葡萄糖与肾脏比率

🧠 为什么重要

SODIUM 135到145 mEq/L；POTASSIUM 3.5到5.0；CHLORIDE约98到106；碳酸氢盐（CO2）22到26。BUN 10到20 mg/dL会在肾功能障碍、脱水、高蛋白摄入、GI出血和使用类固醇时升高。CREATININE约0.6到1.2 mg/dL是更具特异性的肾脏标志物，因为它几乎不受饮食或水合状态影响；肌酐升高意味着GLOMERULAR FILTRATION RATE下降，慢性肾脏病定义为GFR低于60 mL/min/1.73 m²，或存在肾损伤标志物，如尿中有白蛋白，且持续超过3个月。BUN与肌酐的比率高于约20 to 1且肌酐正常时，提示脱水或GI出血；两者按比例同时升高则提示肾实质性疾病。空腹GLUCOSE 70到99 mg/dL为正常，100到125为糖尿病前期，126或更高且出现两次则为糖尿病。HEMOGLOBIN A1c反映2到3个月内的平均血糖：低于5.7%为正常，5.7到6.4%为糖尿病前期，6.5%或以上为糖尿病，治疗目标通常低于7%。CALCIUM 9到10.5 mg/dL，MAGNESIUM 1.5到2.5 mEq/L，PHOSPHORUS 2.5到4.5 mg/dL；钙和磷的变化方向相反。ALBUMIN 3.5到5 g/dL反映营养状况和肝脏合成情况，但白蛋白（和前白蛋白）也会在炎症和急性疾病时下降，因此单凭它们判断营养状况并不可靠；白蛋白偏低会降低总钙并引起水肿。

SODIUM 135 to 145 mEq/L; POTASSIUM 3.5 to 5.0; CHLORIDE about 98 to 106; bicarbonate (CO2) 22 to 26. BUN 10 to 20 mg/dL rises with kidney dysfunction, dehydration, high protein intake, GI bleeding and steroids. CREATININE about 0.6 to 1.2 mg/dL is the more specific kidney marker because it is barely affected by diet or hydration; a rising creatinine means falling GLOMERULAR FILTRATION RATE, and chronic kidney disease is defined as a GFR below 60 mL/min/1.73 m² or markers of kidney damage, such as albumin in the urine, lasting more than 3 months. A BUN-to-creatinine ratio above about 20 to 1 with a normal creatinine suggests dehydration or GI bleeding; both elevated in proportion suggests intrinsic kidney disease. Fasting GLUCOSE 70 to 99 mg/dL is normal, 100 to 125 is prediabetes, and 126 or higher on two occasions is diabetes. HEMOGLOBIN A1c reflects the average glucose over 2 to 3 months: below 5.7% normal, 5.7 to 6.4% prediabetes, 6.5% or above diabetes, with a treatment goal usually below 7%. CALCIUM 9 to 10.5 mg/dL, MAGNESIUM 1.5 to 2.5 mEq/L, PHOSPHORUS 2.5 to 4.5 mg/dL; calcium and phosphorus move in opposite directions. ALBUMIN 3.5 to 5 g/dL reflects nutrition and liver synthesis, but albumin (and prealbumin) also fall with inflammation and acute illness, so they are not reliable on their own for nutrition; low albumin lowers total calcium and causes edema.

🏥 真实场景

💧 一名呕吐了三天的老年患者BUN为52，肌酐为1.1，比率接近47 to 1。护士判断这是肾前性脱水而非肾衰竭，IV输液到早晨时使BUN降了下来。如果肌酐为4.5，比率接近12 to 1，护士就会怀疑肾实质性损伤。该患者仍需要仔细的容量评估和液体补充，以及及时的肾内科评估。

💧 An older adult with vomiting for three days has a BUN of 52 and a creatinine of 1.1, a ratio near 47 to 1. The nurse recognizes prerenal dehydration rather than kidney failure, and IV fluids bring the BUN down by morning. Had the creatinine been 4.5, a ratio near 12 to 1, the nurse would suspect intrinsic kidney injury. The client would still need careful volume assessment and fluid replacement, along with prompt nephrology evaluation.

📌 要点总结

• BUN 10到20，肌酐0.6到1.2；比率超过20 to 1提示脱水BUN 10 to 20, creatinine 0.6 to 1.2; ratio over 20 to 1 suggests dehydration
• 空腹血糖126或更高，或A1c 6.5%或更高，经复查确认即可诊断糖尿病Fasting glucose 126 or higher, or A1c 6.5% or higher, confirmed on repeat testing, diagnoses diabetes
• 白蛋白偏低：水肿和总钙假性偏低Low albumin: edema and a falsely low total calcium

✅ 自我测试