その 基礎代謝パネル — usually shortened to BMP — is a group of eight blood tests that measure key chemicals controlling kidney function, fluid and electrolyte balance, and blood sugar. It is one of the most commonly ordered blood test panels in medicine and is a routine part of evaluating people who are unwell, monitoring people with chronic conditions, and screening healthy adults during check-ups.
The BMP gives doctors a quick snapshot of how the kidneys are filtering waste, how the body is balancing salts and fluids, and how blood sugar is being controlled. This article explains what each component measures, why the test is done, and what abnormal results may mean.
検査結果に適用される基準範囲は、ここに表示されている一般的な範囲ではなく、検査報告書に記載されている範囲です。基準範囲は検査機関によって異なります。 検査結果は、使用する機器、検査対象者、年齢、性別、妊娠状況などの個人差によって異なります。必ずご自身の検査結果に記載されている基準値と比較し、異常な結果が出た場合は医師にご相談ください。
基礎代謝パネルとは何ですか?
A basic metabolic panel is a group of eight measurements performed together on a single blood sample:
- ナトリウム（Na） — an electrolyte that controls fluid balance
- カリウム（K） — an electrolyte that controls heart and muscle function
- 塩化物（Cl） — an electrolyte that helps maintain fluid balance and acid-base balance
- 重炭酸塩（CO2 またはHCO3) — a measure of acid-base balance in the blood
- 血中尿素窒素 (BUN) — a waste product cleared by the kidneys
- クレアチニン — a waste product cleared by the kidneys, the most useful single measure of kidney function
- グルコース — blood sugar
- カルシウム — a mineral important for bones, nerves, muscles, and the heart
The BMP is sometimes called a “chem 7” or “chem 8” — the chem 7 includes everything except calcium, while the chem 8 includes all eight. When the panel is expanded to include liver-related measurements, it becomes a 包括的代謝パネル (CMP).
Why is a BMP done?
The BMP is a versatile screening and monitoring test used in many situations:
- 症状を調査するため。 Confusion, weakness, fatigue, nausea, irregular heartbeat, frequent urination, and many other symptoms can be caused by problems with electrolytes, kidney function, or blood sugar.
- To check kidney function. The BMP includes the most commonly used measures of kidney function and is the standard method for screening for and monitoring chronic kidney disease.
- To monitor known conditions. People with diabetes, kidney disease, heart failure, high blood pressure, and other chronic conditions often have BMPs done regularly.
- 服薬状況を監視するため。 Many medications — including diuretics (“water pills”), ACE inhibitors, certain antibiotics, lithium, and chemotherapy — can affect kidney function or electrolytes.
- 手術前。 A BMP is often part of routine pre-operative testing.
- In emergency settings. The BMP is one of the most commonly ordered tests in the emergency department because it can quickly identify dangerous electrolyte imbalances and acute kidney problems.
- For routine screening. Many doctors include a BMP as part of routine annual health check-ups for adults.
テストはどのように実行されますか？
A BMP is performed on a small sample of blood, usually drawn from a vein in the arm. The blood is collected into a tube and analyzed by automated laboratory equipment. Results are usually available within a few hours.
The glucose component of the BMP is affected by recent food intake, so the test may be ordered as a fasting BMP, requiring eight to twelve hours without food beforehand, or as a non-fasting test. Your doctor will tell you which to do. The other seven components do not require fasting.
Components of the basic metabolic panel
ナトリウム（Na）
Sodium is the body’s most important electrolyte for controlling fluid balance — the amount of water in and around cells, in the blood, and in tissues. It also plays a key role in maintaining acid-base balance and supports nerve and muscle function.
A typical reference range for adults is 135–145 milliequivalents per litre (mEq/L) or millimoles per litre (mmol/L) — these units are equivalent for sodium.
Causes of low sodium (hyponatremia):
- Drinking very large amounts of water (water intoxication)
- Diuretic medications, particularly thiazide diuretics
- Vomiting, diarrhea, or excessive sweating
- Heart failure, kidney disease, and liver disease
- A condition called SIADH (syndrome of inappropriate antidiuretic hormone), which can be caused by certain medications, lung disease, or other conditions
- アジソン病（副腎不全）
- Severe burns or other major fluid losses
Causes of high sodium (hypernatremia):
- Dehydration, the most common cause
- Excessive sweating, fever, or burns without enough fluid replacement
- Diabetes insipidus, a condition in which the kidneys cannot conserve water
- 腎臓病
- Eating very salty foods (rare as a sole cause)
Sodium abnormalities are often more about water balance than about salt itself — a low sodium level usually means too much water relative to sodium, not literally too little salt in the body.
カリウム（K）
Potassium is an electrolyte that is essential for the proper function of the heart, nerves, and muscles. Even small abnormalities in potassium can cause irregular heartbeats and muscle weakness, so potassium results are watched closely.
A typical reference range for adults is 3.5–5.0 millimoles per litre (mmol/L) or milliequivalents per litre (mEq/L).
Causes of low potassium (hypokalemia):
- Diuretic medications, particularly loop and thiazide diuretics
- 嘔吐と下痢
- Inadequate dietary intake (rare in healthy people)
- Certain medications, including some asthma medications and corticosteroids
- Kidney disease in some forms
- Hyperaldosteronism (excess aldosterone hormone)
- Refeeding syndrome (when severely malnourished people resume eating)
Causes of high potassium (hyperkalemia):
- Kidney disease, particularly when significantly impaired
- Medications including ACE inhibitors, angiotensin receptor blockers, potassium-sparing diuretics, and some chemotherapy drugs
- Severe injury, burns, or muscle breakdown
- アジソン病
- A common laboratory artifact in which potassium leaks out of red blood cells during sample collection (called pseudohyperkalemia) — your doctor may want to repeat the test if a high potassium level is unexpected
High potassium can be a medical emergency because it can trigger life-threatening abnormal heart rhythms. Significantly elevated potassium results are usually flagged urgently by the laboratory.
塩化物（Cl）
Chloride is an electrolyte that, along with sodium, helps maintain fluid balance and acid-base balance in the body. It is one of the main negatively charged ions in the blood.
A typical reference range for adults is 96–106 mmol/L.
Chloride levels usually move in parallel with sodium, so abnormal chloride often reflects the same underlying cause as a sodium abnormality (dehydration, fluid overload, vomiting, or diarrhea). Chloride is sometimes most useful when interpreted together with bicarbonate to assess acid-base disorders.
重炭酸塩（CO2 またはHCO3)
Bicarbonate is a chemical that the body uses to maintain acid-base balance — keeping the blood’s pH within a narrow normal range. The BMP measures total carbon dioxide content in the blood, which is mostly bicarbonate, and is reported as either CO2 またはHCO3.
A typical reference range for adults is 22–29 mmol/L.
Causes of low bicarbonate (acidosis):
- 重度の下痢
- 糖尿病性ケトアシドーシス
- 腎臓病
- Sepsis or other causes of poor tissue oxygen delivery
- Certain poisonings (including aspirin and methanol)
Causes of high bicarbonate (alkalosis):
- 持続的な嘔吐
- 利尿薬
- Severe potassium deficiency
- Chronic lung disease such as COPD
血中尿素窒素 (BUN)
Blood urea nitrogen is the amount of nitrogen in the blood that comes from urea, a waste product produced when the body breaks down protein. The kidneys filter urea out of the blood and excrete it in urine, so BUN provides information about kidney function. However, BUN is also affected by hydration status, dietary protein intake, and other factors.
A typical reference range for adults is 6–20 milligrams per decilitre (mg/dL).
Causes of high BUN:
- Kidney disease, the most common cause of a persistently elevated BUN
- 脱水
- 高タンパク質の食事摂取
- Gastrointestinal bleeding (the digested blood is a protein source)
- Heart failure or any condition reducing blood flow to the kidneys
- コルチコステロイドを含む特定の薬剤
Causes of low BUN:
- Severe liver disease (the liver makes urea)
- Low dietary protein intake
- 妊娠
- 水分過剰
BUN is usually interpreted alongside creatinine. The BUN-to-creatinine ratio can help distinguish between different causes of kidney dysfunction.
クレアチニン
Creatinine is a waste product produced by normal muscle activity. It is removed from the blood by the kidneys and excreted in urine. Because production is fairly steady from day to day, blood creatinine is one of the most reliable measures of kidney function — when the kidneys are not filtering normally, creatinine builds up in the blood.
A typical reference range for adults is 0.84–1.21 mg/dL, though the range varies somewhat based on age, sex, and body size. People with more muscle mass typically have higher baseline creatinine levels.
Most laboratories report creatinine alongside an 推定糸球体濾過量（eGFR）, which is a calculated estimate of how well the kidneys are filtering blood. A typical normal eGFR is 90 mL/min/1.73m² or higher. An eGFR below 60 sustained for at least three months is the standard definition of chronic kidney disease.
Causes of high creatinine (impaired kidney function):
- Acute kidney injury, which can be caused by dehydration, low blood pressure, certain medications, or obstruction of the urinary tract
- Chronic kidney disease, often caused by diabetes, high blood pressure, or other chronic conditions
- 心不全
- Certain medications, including some antibiotics, NSAIDs, and contrast dyes used in imaging
- Severe muscle injury (rhabdomyolysis)
Causes of low creatinine:
- Reduced muscle mass, including in older adults
- 重度の肝疾患
- 妊娠
For a more detailed explanation of kidney function tests, see our companion article 腎機能検査について理解する.
グルコース
Glucose is the main sugar in the blood and the body’s primary source of energy. The body controls blood glucose tightly through hormones, particularly insulin. Abnormal blood glucose is the defining feature of diabetes.
The reference range depends on whether the test was done fasting or not:
- 空腹時血糖 (after at least 8 hours without food): a typical reference range is 70–99 mg/dL. Values of 100–125 mg/dL are typically classified as prediabetes; 126 mg/dL or higher on more than one occasion meets the criteria for diabetes.
- Random (non-fasting) glucose: values up to about 140 mg/dL are typical. A random glucose of 200 mg/dL or higher in someone with symptoms of diabetes meets the criteria for diabetes.
Causes of high glucose (hyperglycemia):
- Diabetes (type 1, type 2, or gestational)
- Stress, including acute illness, infection, or recent surgery
- Corticosteroid medications such as prednisone
- Eating before a “fasting” test
- Pancreatic conditions that reduce insulin production
- Certain hormone disorders (Cushing’s syndrome, acromegaly, hyperthyroidism)
Causes of low glucose (hypoglycemia):
- Diabetes medications, particularly insulin and some oral diabetes drugs
- 長期間の絶食
- 過度のアルコール摂取
- 重度の肝臓または腎臓の病気
- 副腎不全
- Certain rare hormone-producing tumours
For a deeper discussion of diabetes testing, see our companion articles ヘモグロビンA1c検査結果の理解 の三脚と 空腹時血糖値と経口ブドウ糖負荷試験について理解する.
カルシウム
Calcium is a mineral that is essential for strong bones and teeth, blood clotting, and the function of nerves, muscles, and the heart. Most of the body’s calcium is stored in bone, and only a small fraction circulates in the blood, but that fraction is tightly regulated.
A typical reference range for total calcium in adults is 8.5–10.2 mg/dL.
Causes of high calcium (hypercalcemia):
- Hyperparathyroidism, a condition in which the parathyroid glands produce too much parathyroid hormone (PTH), the most common cause
- Cancer, including some that produce a PTH-like substance (such as squamous cell lung cancer) and others that spread to bone (such as breast cancer and 多発性骨髄腫)
- Vitamin D excess
- Certain medications, including thiazide diuretics and lithium
- Long periods of immobility
- Inflammatory conditions such as sarcoidosis
Causes of low calcium (hypocalcemia):
- Hypoparathyroidism (too little PTH), often after thyroid or parathyroid surgery
- ビタミンD欠乏症
- 慢性腎臓病
- Severe magnesium deficiency
- 急性膵炎
- 特定の薬
Calcium results are sometimes reported alongside イオン化カルシウム, which measures only the biologically active form of calcium and is not affected by changes in protein levels. Ionized calcium is more accurate but is not part of the routine BMP.
What happens after a BMP?
If your BMP results are within reference ranges, no further investigation is usually needed. If a result is abnormal, the next steps depend on which measurement is abnormal, by how much, and what other findings are present. Some possibilities include:
- テストを繰り返してください。 Mildly abnormal results may resolve on their own or be due to laboratory variability. A repeat test can confirm whether the abnormality is real and persistent.
- 追加の血液検査を実施してください。 Specific patterns prompt targeted follow-up. For example, an elevated calcium often prompts PTH, vitamin D, and phosphorus testing. An elevated creatinine may prompt repeat testing alongside a urine albumin-to-creatinine ratio. An elevated glucose typically prompts hemoglobin A1c testing.
- 画像処理を注文する。 Persistent kidney abnormalities may prompt an ultrasound of the kidneys.
- 薬の量を調整する。 Some abnormalities — particularly involving potassium, sodium, or kidney function — may prompt your doctor to change a dose or stop a medication.
- Review diet and fluid intake. Some abnormalities, particularly involving sodium, glucose, or BUN, can be improved by dietary changes.
- 専門医に紹介してください。 Persistent or significant kidney function abnormalities may prompt referral to a nephrologist (kidney specialist). Calcium and parathyroid abnormalities may prompt referral to an endocrinologist.
An abnormal BMP result is not in itself a diagnosis. The BMP is a starting point, and your doctor will interpret the results in the context of your symptoms, medical history, medications, and any other test results.
医師に尋ねるべき質問
- Were any of my BMP results outside the reference range?
- 検査結果が異常だった場合、その異常はどの程度重大なものなのか？
- Could any of my medications be affecting my results?
- 検査を繰り返すべきか、もし繰り返すならいつ繰り返すべきか？
- Do I need any follow-up tests, such as a comprehensive metabolic panel, hemoglobin A1c, or imaging?
- What is my eGFR, and what does it mean for my kidney function?
- Are there changes I can make to my diet, fluid intake, or activity that would improve my results?
- 専門医に診てもらう必要がありますか?
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