23 一位9歲小男童因生長遲緩至門診求診。動脈氣體分析（arterial blood gas）顯示：pH: 7.35，PaCO2: 32 mmHg，HCO3��: 14.5 mmol/L，BE: -6.8 mmol/L，Na+: 138 mmol/L，K+: 4.4 mmol/L，Cl��: 112 mmol/L，下列那一項敘述最不正確？

此病人血中之anion gap為正常

此病人要做FeHCO3（fraction excretion of HCO3��）檢查，以確立診斷

腎臟可能有鈣化現象

urine之anion gap一定是正值（positive）

this patient has metabolic acidosis: evident by the low HCO3 14.5:

anion gap is : (na +k)- Cl - HCO3

The average anion gap for healthy adults is 8-12 mEq/L

Urine anion gap is calculated by subtracting the urine concentration of chloride (anions) from the concentrations of sodium plus potassium (cations):

= Na⁺ + K⁺ − Cl^{− - HCO3}

^{if more HCO3 is being excreted into urine. the urine anion gap could be negative.}