抽血？ 驗尿？ 還是都要？ Blood Test? Urine Test? Or Both?

醫生為什麼有時要你抽血，有時又要你驗尿？這完全取決於不同物質在我們體內有不同的「旅行路徑」。選錯了，就像想去高雄卻搭了往基隆的車，永遠到不了目的地。 Why do doctors sometimes ask for a blood test, and other times a urine test? It depends on the different “travel paths” substances take in our body. Choosing the wrong one is like taking a train to Keelung when you want to go to Kaohsiung—you’ll never reach your destination.

血液檢測：捕捉「正在路上」的證據 Blood Test: Capturing “In-Transit” Evidence

血液就像身體的高速公路，檢測血液主要能反映「近期」或「正在發生」的暴露。最適合用來抓那些剛進入體內，還在血液中趴趴走的物質。像是鉛(Pb)，95%以上都跟紅血球黏在一起，不抽血根本找不到；還有來自海鮮的有機汞(Hg)，也主要待在血液裡。 Blood is like the body’s highway. A blood test primarily reflects “recent” or “ongoing” exposure. It’s best for catching substances that have just entered the body and are still circulating. For example, over 95% of lead (Pb) binds to red blood cells and can only be found through a blood test. Organic mercury (Hg) from seafood also mainly stays in the blood.

尿液檢測：看看身體排出了什麼 Urine Test: Seeing What the Body Excretes

尿液是身體的「排毒管道」，檢測尿液可以看出身體正努力把哪些物質排出去。它既能評估近期暴露，也能反映長期累積。對於主要靠腎臟代謝的無機砷(As)、無機汞(Hg)、鉻(Cr)、鎘(Cd)等，尿液是最好的監測工具。 Urine is the body’s “detox pipeline.” A urine test shows what substances the body is trying to eliminate. It can assess both recent exposure and long-term accumulation. For substances mainly metabolized by the kidneys, like inorganic arsenic (As), inorganic mercury (Hg), chromium (Cr), and cadmium (Cd), urine is the best monitoring tool.

關鍵小知識：為什麼要「校正肌酸酐」？ Key Fact: Why “Creatinine Correction”?

你喝水多，尿就稀；喝水少，尿就濃。單次的尿液濃度很容易失準。而「肌酸酐(Creatinine)」是我們肌肉代謝的穩定產物，排泄率很固定。所以，把物質濃度除以肌酸酐濃度，就像給數字上了一層「防手震」，能校正掉飲水量的干擾，讓結果更準確、更有可比性！ If you drink a lot of water, your urine is diluted; if you drink less, it’s concentrated. A single urine sample can be inaccurate. “Creatinine” is a stable product of muscle metabolism excreted at a constant rate. Dividing a substance’s concentration by creatinine concentration is like adding “image stabilization” to the number, correcting for hydration levels and making the result more accurate and comparable.

檢測項目大亂鬥？一張總表看懂關鍵差異 Test Overload? A Summary Chart to See the Difference

看得眼花撩亂了嗎？別擔心，這張總覽表幫你快速整理重點，讓你秒懂「在什麼情況下，該做什麼檢測」。 Feeling overwhelmed? Don’t worry, this summary chart helps you quickly grasp the key points and understand “which test to do under what circumstances.”