BMP

Order Code

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142

Preferred Specimen

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Collect 2 mL of serum. Allow the SST tube to clot upright for at least 30 minutes, then centrifuge within 2 hours of collection. Store refrigerated.

ContainerType

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Serum separator tube

Alternate Specimen Requirements

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Collect 2 mL of serum using a plain red-top tube. Allow the specimen to clot upright for a minimum of 60 minutes. Then centrifuge, transfer the serum into a plastic transport tube within 2 hours, and clearly label it as “serum from red-top tube.” Store refrigerated.

Minimum Volume

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2 mL

Transport Temperature

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Refrigerated

Expected Turnaround Time

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1 day room temperature; 1 week refrigerated

Specimen Stability

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Fresh urine:1 day refrigerated BD urine preservative tube:3 days room temperature

Methodology

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Roche COBAS automated methodology or other
automated chemistry method.

Overview

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The Basic Metabolic Panel (BMP) consists of seven or eight biochemical assays that assess electrolyte balance, renal function, and glucose concentration. When interpreted in concert, abnormal results may provide insights into potential disease processes requiring further investigation (AACC, 2020).

A BMP typically includes:

• Sodium (Na⁺) — primarily extracellular; plays a central role in regulating water distribution
• Potassium (K⁺) — primarily intracellular; small plasma changes can significantly affect cardiac function
• Chloride (Cl⁻) — moves with sodium across cell membranes to support electrical and osmotic equilibrium
• Bicarbonate (HCO₃⁻) — helps maintain acid–base balance through renal mechanisms
• BUN (Blood Urea Nitrogen) — a byproduct of protein metabolism, filtered by the kidneys; used as a marker of renal function
• Creatinine (Cr) — derived from muscle metabolism; indicates renal filtration capacity
• Calcium (Ca²⁺) — mostly stored in bone; circulating levels are tightly controlled hormonally
• Glucose (Glc) — the body’s principal fuel source, regulated by diet, hormones, and metabolism

Some laboratories may choose not to report calcium depending on their BMP panel configuration.

Clinical Significance

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• Used in routine health screening
• Detects disturbances in fluid or electrolyte balance
• Helps assess acid–base imbalances
• Aids in diagnoses when symptoms such as edema, nausea, weakness, confusion, or arrhythmia are present
• Monitors acute or chronic conditions (e.g., hypertension, heart failure, liver or kidney disease, diabetes)
• Evaluates effects of medications that may alter electrolyte levels (e.g., diuretics)

Additional Information

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Although sodium, potassium, chloride, and bicarbonate are often measured as a group (electrolyte panel), each can be ordered individually when clinically indicated. Other essential electrolytes—such as calcium, magnesium, and phosphate—may also be requested separately (AACC, 2019).

Interpretative Information

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Sodium:

Hypernatremia (>150 mEq/L)

• Common causes:
  • Dehydration (eg, diuretics, vomiting or diarrhea, increased free water loss from fever, sweating, or burns)
  • Drug side effect (eg, anabolic steroids, corticosteroids, laxatives, cough medicines, and oral contraceptives)
• Less obvious causes:
  • Cushing syndrome
  • Central or nephrogenic diabetes insipidus with insufficient free water
  • Hyperaldosteronism
  • Excessive salt intake

Hyponatremia (<125 mEq/L)

• Common causes:
  • Hypervolemic
    • Dilution due to water retention (eg, decompensated heart failure, advanced liver cirrhosis, renal failure)
  • Euvolemic
    • Hypothyroidism
    • Syndrome of inappropriate secretion of antidiuretic hormone (SIADH)
    • Glucocorticoid deficiency
    • Beer potomania
    • Psychogenic polydipsia
  • Hypovolemic
    • Diarrhea or vomiting
    • Diuretic use
    • Mineralocorticoid deficiency
    • Third spacing (ileus, pancreatitis)
• Pseudohyponatremia may occur in the presence of very high glucoses (eg, diabetic ketoacidosis or nonketotic hyperosmolar coma)
  • Sodium is artificially decreased by 1.3-1.6 mEq/L for each 100 mg/dL increase in glucose. Apparent mild hyponatremia with very high glucose may actually mean hypernatremia.

Potassium:

Hyperkalemia (>6.5 mEq/L)

• Excessive intake or administration
• Medications (eg, K⁺ salts of some drugs, ACE inhibitors, NSAIDs, Aldactone, high-dose trimethoprim-sulfamethoxazole therapy)
• Mobilization of potassium from cells (eg, trauma, malignant hyperthermia)
• Inadequate renal excretion (renal insufficiency)
• Addison disease
• Acidosis (eg, diabetic ketoacidosis or lactic acidosis)
• Lack of insulin
• Renal tubular disorders
• Artifact causing hyperkalemia includes hemolysis from collection, storage, or processing

Hypokalemia (<2.5 mEq/L)

• Drug-induced (eg, diuretics, bronchodilators, mineralocorticoids, high-dose glucocorticoids, high-dose penicillin, aminoglycosides, cisplatin, foscarnet, amphotericin B)
• Found in 80% to 90% of hypertensive patients with primary aldosteronism
• Parenteral deprivation of K⁺ (eg, parenteral therapy without adequate K⁺ replacement)
• GI loss (vomiting, diarrhea, bypass, enteric fistulas, malabsorption)
• Malnutrition (including alcoholism)
• Alkalosis
• Renal tubular disorders

Chloride:

Hyperchloridemia (>115 mEq/L)

• Hyperchloremic (nonanion gap) metabolic acidosis
  • Excessive infusion of hyperchloremic (normal) saline
  • Diarrhea/GI losses
  • Renal tubular acidosis
  • Pancreatic fistula
  • Enterovesical fistula
• Mineralocorticoid deficiency

Hypochloridemia (<80 mEq/L)

• Vomiting or gastric suction
• Overhydration
• Syndrome of inappropriate secretion of ADH
• Chronic or compensated respiratory acidosis
• Burns
• Diuretic therapy

Bicarbonate: Along with anion gap (see Pearls), HCO₃^– is used as a preliminary screen for abnormalities in acid-base balance:

Elevated HCO₃^– (>30 mEq/L)

• Metabolic alkalosis, usually acute and often accompanied by hypokalemia
• Compensated respiratory acidosis
• Increased cortisol or aldosterone causing metabolic alkalosis from urinary losses of hydrogen and potassium ions

Decreased HCO₃^– (<10 mEq/L)

• Metabolic acidosis
• Compensated respiratory alkalosis
• Hyperchloremic (nonanion gap) metabolic acidosis − decreased HCO₃^– with high chloride and normal anion gap (eg, diarrhea and renal tubular acidosis)
• Drug-induced (eg, methicillin, nitrofurantoin, tetracycline, thiazide diuretics)

BUN (blood urea nitrogen):

Elevated BUN (>100 mg/dL)

• Kidney disease
• Urinary tract obstruction (stone, stricture, external compression)
• Decreased blood flow to the kidneys (dehydration, heart failure, shock, severe burns)
• Gastrointestinal bleeding (upper GI such as stomach, esophageal)
• Increased protein breakdown (sepsis, fevers)
• High protein diets
• Increasing age (in particular, over age 60)
• Drug-induced (eg, aminoglycosides, cephalosporins, diuretics, steroids)

Decreased BUN (<7 mg/dL)

• Uncommon and not usually a cause for concern
• Malnutrition (eg, cancer, advanced liver disease, alcoholism)
• Overhydration
• Drug-induced (eg, chloramphenicol, streptomycin)

Creatinine:

Elevated (>8 mg/dL)

• Prerenal causes of reduced blood flow to the kidney (dehydration, heart failure, shock, renal artery stenosis)
• Damage to renal vasculature (diabetes, hypertension, glomerulonephritis due to infection or autoimmune diseases)
• Bacterial infection of kidneys (pyelonephritis)
• Damage to renal collecting tubules (acute tubular necrosis due to drugs, shock, or toxins)
• Postrenal obstruction (kidney stone, prostate hypertrophy)

Decreased:

• Uncommon and are not usually a cause for concern
• May be seen in decreased muscle mass

Glucose:

Hyperglycemia (>99 mg/dL)

• Diabetes mellitus, I or II
• Acute physiologic stress (trauma, myocardial infarction, infection)
• Endocrinopathies (eg, acromegaly, Cushing disease or syndrome, hyperthyroidism)

Hypoglycemia (<65 mg/dL)

• Hepatic dysfunction (eg, cirrhosis)
• Severe heart failure
• Sepsis
• Endocrinopathies (eg, hypothyroidism, hypopituitarism)
• Tumors (insulinomas)
• Accidental or deliberate misuse of hypoglycemics (insulin or oral glucose-lowering medications)

Calcium:

Hypercalcemia (>10.3 mg/dL)

• Hyperparathyroidism
• Cancer (excessive secretion of parathyroid hormone-related protein, bony metastasis)
• Disease (eg, sarcoidosis, tuberculosis)
• Prolonged immobilization
• Drug-induced (eg, thiazide diuretics, lithium, tamoxifen, excessive vitamin D intake)

Hypocalcemia (<8.5 mg/dL)

• Hypoalbuminemia (most common; results in a decrease in bound calcium, ionized calcium levels remains normal)
• Hypoparathyroidism
• Renal failure
• Deficiency of dietary calcium, magnesium, or vitamin D
• Increased levels of phosphorus
• Acute pancreatitis

Limitations

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Potassium:

• Falsely elevated reading due to blood cell hemolysis from poor collection technique causing the lysis of cells and subsequent release of high concentrations of intracellular potassium.
• Falsely elevated reading due to prolonged contact of serum with cells if a specimen has sat unattended for several hours.

Bicarbonate:

• Falsely low reading if specimen is exposed to air causing loss of carbon dioxide
• Falsely low reading from inadequate filling of red top evacuated collection tubes
• Falsely low reading (as much as 10 mmol/L) if specimen is excessively diluted with heparin (use only enough heparin sufficient to fill the dead space of the syringe)

Creatinine:

• Falsely low reading when high concentrations of NAPQI (an acetaminophen metabolite) or N-acetylcysteine (NAC) are present
• Normal serum creatinine results do not rule out renal dysfunction as the serum creatinine is not sensitive to early renal damage.

References

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Diagnostic Role

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The basic metabolic panel (BMP) is ordered during both routine health exams and in acute evaluations to identify electrolyte, fluid, metabolic imbalance (acidosis or alkalosis), renal function, and/or glucose abnormalities. The BMP is used to screen for conditions such as diabetes or renal disease, as well as monitor known conditions, such as hypertension (AACC 2020).

Results are evaluated for both individual lab abnormalities as well as together to identify patterns that may identify or suggest underlying pathology, such as dehydration, renal or pulmonary disease, or endocrine abnormalities. A series of BMPs may be followed over time to monitor interventions (AACC 2019). If the resulted values do not correlate with clinical findings, hemolysis or laboratory error needs to be ruled out, typically by resubmitting a new blood sample for the laboratory to analyze.

Alias

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• Bmp

Test Setup Days

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Monday through Friday

CPT

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80048 AMA Defined Panel.