Basic metabolic panel: Difference between revisions
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The '''Basic Metabolic Panel''' (BMP), often referred to as a '''Chem-7''' or '''SMA-7''', is one of the most frequently ordered laboratory tests in the Emergency Department. It provides a rapid assessment of fluid status, electrolytes, renal function, and glucose levels.<ref name="pmid32443130">Bertschi LA. Abnormal Basic Metabolic Panel Findings: Implications for Nursing. Am J Nurs. 2020 Jun;120(6):48-55. [https://pubmed.ncbi.nlm.nih.gov/32443130/ PubMed Abstract]</ref>
The '''Basic Metabolic Panel''' (BMP), often referred to as a '''Chem-7''' or '''SMA-7''', is one of the most frequently ordered laboratory tests in the Emergency Department. It provides a rapid assessment of fluid status, electrolytes, renal function, and glucose levels.<ref name="pmid32443130">Bertschi LA. Abnormal Basic Metabolic Panel Findings: Implications for Nursing. Am J Nurs. 2020 Jun;120(6):48-55. [https://pubmed.ncbi.nlm.nih.gov/32443130/ PubMed Abstract]</ref>


Including [[Calcium]] technically makes the panel a '''Chem-8'''. It differs from the [[Comprehensive Metabolic Panel]] (CMP) by the lack of [[Liver Function Tests]] (LFTs).
Including [[Calcium]] technically makes the panel a Chem-8. It differs from the [[Comprehensive Metabolic Panel]] (CMP) by the lack of [[Liver Function Tests]] (LFTs).


==Components and Reference Ranges==
==Components and Reference Ranges==
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! Component !! Abbreviation !! Normal Range (US) !! SI Units
! Component !! Abbreviation !! Normal Range (US) !! SI Units
|-
|-
| [[[Has LabTest::Sodium]] || Na || 135 – 145 mEq/L || 135 – 145 mmol/L
| [[Has LabTest::Sodium]] || Na || 135 – 145 mEq/L || 135 – 145 mmol/L
|-
|-
| [[[Has LabTest::Potassium]] || K || 3.5 – 5.0 mEq/L || 3.5 – 5.0 mmol/L
| [[Has LabTest::Potassium]] || K || 3.5 – 5.0 mEq/L || 3.5 – 5.0 mmol/L
|-
|-
| [[[Has LabTest::Chloride]] || Cl || 95 – 105 mEq/L || 95 – 105 mmol/L
| [[Has LabTest::Chloride]] || Cl || 95 – 105 mEq/L || 95 – 105 mmol/L
|-
|-
| [[[Has LabTest::Bicarbonate]] (Total CO2) || HCO3 / CO2 || 22 – 29 mEq/L || 22 – 29 mmol/L
| [[Has LabTest::Bicarbonate]] (Total CO2) || HCO3 / CO2 || 22 – 29 mEq/L || 22 – 29 mmol/L
|-
|-
| [[[Has LabTest::Blood Urea Nitrogen]] || BUN || 7 – 20 mg/dL || 2.5 – 7.1 mmol/L
| [[Has LabTest::Blood Urea Nitrogen]] || BUN || 7 – 20 mg/dL || 2.5 – 7.1 mmol/L
|-
|-
| [[[Has LabTest::Creatinine]] || Cr || 0.6 – 1.2 mg/dL || 53 – 106 µmol/L
| [[Has LabTest::Creatinine]] || Cr || 0.6 – 1.2 mg/dL || 53 – 106 µmol/L
|-
|-
| [[[Has LabTest::Glucose]] || Glu || 70 – 100 mg/dL (fasting) || 3.9 – 5.6 mmol/L
| [[Has LabTest::Glucose]] || Glu || 70 – 100 mg/dL (fasting) || 3.9 – 5.6 mmol/L
|-
|-
| [[[Has LabTest::Calcium]] || Ca || 8.5 – 10.2 mg/dL || 2.1 – 2.6 mmol/L
| [[Has LabTest::Calcium]] || Ca || 8.5 – 10.2 mg/dL || 2.1 – 2.6 mmol/L
|}
|}


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===Sodium (Na)===
===Sodium (Na)===
* '''[[Hyponatremia]] (<135):'''
* [[Hyponatremia]] (<135):
** <120 mEq/L is a critical value (Risk of [[Seizure]], coma).<ref name="pmid10816188">Adrogué HJ, Madias NE. Hyponatremia. N Engl J Med. 2000 May 25;342(21):1581-9. [https://pubmed.ncbi.nlm.nih.gov/10816188/ PubMed Abstract]</ref>
** <120 mEq/L is a critical value (Risk of [[Seizure]], coma).<ref name="pmid10816188">Adrogué HJ, Madias NE. Hyponatremia. N Engl J Med. 2000 May 25;342(21):1581-9. [https://pubmed.ncbi.nlm.nih.gov/10816188/ PubMed Abstract]</ref>
** Assess volume status (Hypovolemic, Euvolemic, Hypervolemic).
** Assess volume status (Hypovolemic, Euvolemic, Hypervolemic).
** ''Pearls:'' rule out Pseudohyponatremia (Hyperlipidemia/Hyperproteinemia) and Hyperglycemic induced (Corrected Na = Measured Na + 1.6 * [(Glucose - 100) / 100]).<ref name="pmid10225241">Hillier TA, Abbott RD, Barrett EJ. Hyponatremia: evaluating the correction factor for hyperglycemia. Am J Med. 1999 Apr;106(4):399-403. [https://pubmed.ncbi.nlm.nih.gov/10225241/ PubMed Abstract]</ref>
** ''Pearls:'' rule out Pseudohyponatremia (Hyperlipidemia/Hyperproteinemia) and Hyperglycemic induced (Corrected Na = Measured Na + 1.6 * [(Glucose - 100) / 100]).<ref name="pmid10225241">Hillier TA, Abbott RD, Barrett EJ. Hyponatremia: evaluating the correction factor for hyperglycemia. Am J Med. 1999 Apr;106(4):399-403. [https://pubmed.ncbi.nlm.nih.gov/10225241/ PubMed Abstract]</ref>
* '''[[Hypernatremia]] (>145):'''
* [[Hypernatremia]] (>145):
** Almost always implies free water deficit ([[Dehydration]]).
** Almost always implies free water deficit ([[Dehydration]]).
** Calculate Free Water Deficit.
** Calculate Free Water Deficit.


===Potassium (K)===
===Potassium (K)===
* '''[[Hyperkalemia]] (>5.0):'''
* [[Hyperkalemia]] (>5.0):
** ''Emergency:'' >6.0 or any ECG changes ([[Peaked T waves]], QRS widening, Sine wave).
** ''Emergency:'' >6.0 or any ECG changes ([[Peaked T waves]], QRS widening, Sine wave).
** Causes: [[Renal Failure]], [[Rhabdomyolysis]], missed dialysis, [[Acidosis]] (shifts K out of cells), [[Hemolysis]] (lab error).<ref name="pmid18272089">Montague BT, Ouellette JR, Buller GK. Retrospective review of the frequency of ECG changes in hyperkalemia. Clin J Am Soc Nephrol. 2008 Mar;3(2):324-30. [https://pubmed.ncbi.nlm.nih.gov/18272089/ PubMed Abstract]</ref>
** Causes: [[Renal Failure]], [[Rhabdomyolysis]], missed dialysis, [[Acidosis]] (shifts K out of cells), [[Hemolysis]] (lab error).<ref name="pmid18272089">Montague BT, Ouellette JR, Buller GK. Retrospective review of the frequency of ECG changes in hyperkalemia. Clin J Am Soc Nephrol. 2008 Mar;3(2):324-30. [https://pubmed.ncbi.nlm.nih.gov/18272089/ PubMed Abstract]</ref>
* '''[[Hypokalemia]] (<3.5):'''
* [[Hypokalemia]] (<3.5):
** Causes: Diuretics, GI loss (diarrhea/vomiting).
** Causes: Diuretics, GI loss (diarrhea/vomiting).
** ''Emergency:'' Arrhythmias, U-waves, respiratory muscle weakness.
** ''Emergency:'' Arrhythmias, U-waves, respiratory muscle weakness.
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===Chloride (Cl)===
===Chloride (Cl)===
* Generally follows Sodium status.
* Generally follows Sodium status.
* '''Hyperchloremia:''' Often iatrogenic from large volume [[Normal Saline]] resuscitation (Non-gap metabolic acidosis).
* Hyperchloremia: Often iatrogenic from large volume [[Normal saline]] resuscitation (Non-gap metabolic acidosis).
* '''Hypochloremia:''' Gastric outlet obstruction/vomiting (Metabolic alkalosis).<ref name="pmid25295502" />
* Hypochloremia: Gastric outlet obstruction/vomiting (Metabolic alkalosis).<ref name="pmid25295502" />


===Bicarbonate (CO2)===
===Bicarbonate (CO2)===
* Represents total venous CO2 content (mostly HCO3).
* Represents total venous CO2 content (mostly HCO3).
* '''Low (<22):''' [[Metabolic Acidosis]] (most common in ED) or compensation for respiratory alkalosis.
* Low (<22): [[Metabolic Acidosis]] (most common in ED) or compensation for respiratory alkalosis.
** Calculate [[Anion Gap]] (see below).
** Calculate [[Anion Gap]] (see below).
* '''High (>29):''' [[Metabolic Alkalosis]] or compensation for chronic [[COPD]] (Respiratory acidosis).
* High (>29): [[Metabolic Alkalosis]] or compensation for chronic [[COPD]] (Respiratory acidosis).


===BUN and Creatinine===
===BUN and Creatinine===
* '''[[Acute Kidney Injury]] (AKI):'''
* [[Acute Kidney Injury]] (AKI):
** '''Prerenal:''' BUN:Cr ratio > 20:1. (Dehydration, poor perfusion).
** Prerenal: BUN:Cr ratio > 20:1. (Dehydration, poor perfusion).
** '''Intrinsic:''' BUN:Cr ratio < 15:1. (ATN, AIN, Glomerulonephritis).
** Intrinsic: BUN:Cr ratio < 15:1. (ATN, AIN, Glomerulonephritis).
** '''Postrenal:''' Obstruction (Stones, BPH).
** Postrenal: Obstruction (Stones, BPH).
* ''Pearl:'' Isolated elevated BUN (with normal Cr) is a sensitive indicator for [[Upper GI Bleed]] (digested hemoglobin).<ref name="pmid22396504">Srygley FD, Gerardo CJ, Tran T, Fisher DA. Does this patient have a severe upper gastrointestinal bleed? JAMA. 2012 Mar 14;307(10):1072-9. [https://pubmed.ncbi.nlm.nih.gov/22396504/ PubMed Abstract]</ref>
* ''Pearl:'' Isolated elevated BUN (with normal Cr) is a sensitive indicator for [[Upper GI Bleed]] (digested hemoglobin).<ref name="pmid22396504">Srygley FD, Gerardo CJ, Tran T, Fisher DA. Does this patient have a severe upper gastrointestinal bleed? JAMA. 2012 Mar 14;307(10):1072-9. [https://pubmed.ncbi.nlm.nih.gov/22396504/ PubMed Abstract]</ref>


===Glucose===
===Glucose===
* '''[[Hypoglycemia]] (<70):''' AMS, diaphoresis, seizure. Treat with D50/D10.
* [[Hypoglycemia]] (<70): AMS, diaphoresis, seizure. Treat with D50/D10.
* '''[[Hyperglycemia]]:'''
* [[Hyperglycemia]]:
** >250 with AG Metabolic Acidosis + Ketones = [[Diabetic Ketoacidosis]] (DKA).<ref name="pmid2754687">Kitabchi AE, Umpierrez GE, Murphy MB, et al. Management of hyperglycemic crises in patients with diabetes. Diabetes Care. 2001 Jan;24(1):131-53. [https://pubmed.ncbi.nlm.nih.gov/11194218/ PubMed Abstract]</ref>
** >250 with AG Metabolic Acidosis + Ketones = [[Diabetic Ketoacidosis]] (DKA).<ref name="pmid2754687">Kitabchi AE, Umpierrez GE, Murphy MB, et al. Management of hyperglycemic crises in patients with diabetes. Diabetes Care. 2001 Jan;24(1):131-53. [https://pubmed.ncbi.nlm.nih.gov/11194218/ PubMed Abstract]</ref>
** >600 with high osmolarity + no acidosis = [[Hyperosmolar hyperglycemic state]].
** >600 with high osmolarity + no acidosis = [[Hyperosmolar hyperglycemic state]].
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* Used to differentiate causes of Metabolic Acidosis.<ref name="pmid17699401">Kraut JA, Madias NE. Serum anion gap: its uses and limitations in clinical medicine. Clin J Am Soc Nephrol. 2007 Jan;2(1):162-74. [https://pubmed.ncbi.nlm.nih.gov/17699401/ PubMed Abstract]</ref>
* Used to differentiate causes of Metabolic Acidosis.<ref name="pmid17699401">Kraut JA, Madias NE. Serum anion gap: its uses and limitations in clinical medicine. Clin J Am Soc Nephrol. 2007 Jan;2(1):162-74. [https://pubmed.ncbi.nlm.nih.gov/17699401/ PubMed Abstract]</ref>
* Formula: <math>AG = Na - (Cl + HCO3)</math>
* Formula: <math>AG = Na - (Cl + HCO3)</math>
* '''Normal:''' 8–12 (varies by assay; >12 usually abnormal).
* Normal: 8–12 (varies by assay; >12 usually abnormal).
* '''High Gap Causes (MUDPILES):''' Methanol, Uremia, DKA, Paraldehyde, Iron/INH, Lactic Acidosis, Ethylene Glycol, Salicylates.
* High Gap Causes (MUDPILES): Methanol, Uremia, DKA, Paraldehyde, Iron/INH, Lactic Acidosis, Ethylene Glycol, Salicylates.
* ''Note:'' [[Hypoalbuminemia]] lowers the baseline AG. Corrected AG = Observed AG + 2.5 * (4 - Albumin).
* ''Note:'' [[Hypoalbuminemia]] lowers the baseline AG. Corrected AG = Observed AG + 2.5 * (4 - Albumin).


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* If albumin is low, total calcium appears falsely low.
* If albumin is low, total calcium appears falsely low.
* Formula: {Corrected Ca} = {Measured Ca} + 0.8  (4 - {Albumin})<ref name="pmid4758544">Payne RB, Little AJ, Williams RB, Milner JR. Interpretation of serum calcium in patients with abnormal serum proteins. Br Med J. 1973 Dec 15;4(5893):643-6. [https://pubmed.ncbi.nlm.nih.gov/4758544/ PubMed Abstract]</ref>
* Formula: {Corrected Ca} = {Measured Ca} + 0.8  (4 - {Albumin})<ref name="pmid4758544">Payne RB, Little AJ, Williams RB, Milner JR. Interpretation of serum calcium in patients with abnormal serum proteins. Br Med J. 1973 Dec 15;4(5893):643-6. [https://pubmed.ncbi.nlm.nih.gov/4758544/ PubMed Abstract]</ref>
* Or check an '''Ionized Calcium''' (iCa).
* Or check an Ionized Calcium (iCa).


==See Also==
==See Also==
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[[Category:Critical Care]]
[[Category:Critical Care]]
[[Category:Renal]]
[[Category:Renal]]
[[Category:Labs]]

Latest revision as of 09:28, 22 March 2026

Background

The Basic Metabolic Panel (BMP), often referred to as a Chem-7 or SMA-7, is one of the most frequently ordered laboratory tests in the Emergency Department. It provides a rapid assessment of fluid status, electrolytes, renal function, and glucose levels.[1]

Including Calcium technically makes the panel a Chem-8. It differs from the Comprehensive Metabolic Panel (CMP) by the lack of Liver Function Tests (LFTs).

Components and Reference Ranges

Reference ranges vary by laboratory. Typical adult values are listed below.[2]

Component Abbreviation Normal Range (US) SI Units
Sodium Na 135 – 145 mEq/L 135 – 145 mmol/L
Potassium K 3.5 – 5.0 mEq/L 3.5 – 5.0 mmol/L
Chloride Cl 95 – 105 mEq/L 95 – 105 mmol/L
Bicarbonate (Total CO2) HCO3 / CO2 22 – 29 mEq/L 22 – 29 mmol/L
Blood Urea Nitrogen BUN 7 – 20 mg/dL 2.5 – 7.1 mmol/L
Creatinine Cr 0.6 – 1.2 mg/dL 53 – 106 µmol/L
Glucose Glu 70 – 100 mg/dL (fasting) 3.9 – 5.6 mmol/L
Calcium Ca 8.5 – 10.2 mg/dL 2.1 – 2.6 mmol/L

Interpretation

Sodium (Na)

  • Hyponatremia (<135):
    • <120 mEq/L is a critical value (Risk of Seizure, coma).[3]
    • Assess volume status (Hypovolemic, Euvolemic, Hypervolemic).
    • Pearls: rule out Pseudohyponatremia (Hyperlipidemia/Hyperproteinemia) and Hyperglycemic induced (Corrected Na = Measured Na + 1.6 * [(Glucose - 100) / 100]).[4]
  • Hypernatremia (>145):
    • Almost always implies free water deficit (Dehydration).
    • Calculate Free Water Deficit.

Potassium (K)

Chloride (Cl)

  • Generally follows Sodium status.
  • Hyperchloremia: Often iatrogenic from large volume Normal saline resuscitation (Non-gap metabolic acidosis).
  • Hypochloremia: Gastric outlet obstruction/vomiting (Metabolic alkalosis).[2]

Bicarbonate (CO2)

  • Represents total venous CO2 content (mostly HCO3).
  • Low (<22): Metabolic Acidosis (most common in ED) or compensation for respiratory alkalosis.
  • High (>29): Metabolic Alkalosis or compensation for chronic COPD (Respiratory acidosis).

BUN and Creatinine

  • Acute Kidney Injury (AKI):
    • Prerenal: BUN:Cr ratio > 20:1. (Dehydration, poor perfusion).
    • Intrinsic: BUN:Cr ratio < 15:1. (ATN, AIN, Glomerulonephritis).
    • Postrenal: Obstruction (Stones, BPH).
  • Pearl: Isolated elevated BUN (with normal Cr) is a sensitive indicator for Upper GI Bleed (digested hemoglobin).[6]

Glucose

Calculations

Anion Gap (AG)

  • Used to differentiate causes of Metabolic Acidosis.[8]
  • Formula: <math>AG = Na - (Cl + HCO3)</math>
  • Normal: 8–12 (varies by assay; >12 usually abnormal).
  • High Gap Causes (MUDPILES): Methanol, Uremia, DKA, Paraldehyde, Iron/INH, Lactic Acidosis, Ethylene Glycol, Salicylates.
  • Note: Hypoalbuminemia lowers the baseline AG. Corrected AG = Observed AG + 2.5 * (4 - Albumin).

Corrected Sodium (Hyperglycemia)

  • Formula: {Corrected Na} = {Measured Na} + 0.016 {Glucose} - 100)[4]

Calcium Correction

  • If albumin is low, total calcium appears falsely low.
  • Formula: {Corrected Ca} = {Measured Ca} + 0.8 (4 - {Albumin})[9]
  • Or check an Ionized Calcium (iCa).

See Also

References

  1. ↑ Bertschi LA. Abnormal Basic Metabolic Panel Findings: Implications for Nursing. Am J Nurs. 2020 Jun;120(6):48-55. PubMed Abstract
  2. ↑ 2.0 2.1 Berend K, de Vries AP, GansRO. Physiological approach to assessment of acid-base disturbances. N Engl J Med. 2014 Oct 9;371(15):1434-45. PubMed Abstract
  3. ↑ Adrogué HJ, Madias NE. Hyponatremia. N Engl J Med. 2000 May 25;342(21):1581-9. PubMed Abstract
  4. ↑ 4.0 4.1 Hillier TA, Abbott RD, Barrett EJ. Hyponatremia: evaluating the correction factor for hyperglycemia. Am J Med. 1999 Apr;106(4):399-403. PubMed Abstract
  5. ↑ Montague BT, Ouellette JR, Buller GK. Retrospective review of the frequency of ECG changes in hyperkalemia. Clin J Am Soc Nephrol. 2008 Mar;3(2):324-30. PubMed Abstract
  6. ↑ Srygley FD, Gerardo CJ, Tran T, Fisher DA. Does this patient have a severe upper gastrointestinal bleed? JAMA. 2012 Mar 14;307(10):1072-9. PubMed Abstract
  7. ↑ Kitabchi AE, Umpierrez GE, Murphy MB, et al. Management of hyperglycemic crises in patients with diabetes. Diabetes Care. 2001 Jan;24(1):131-53. PubMed Abstract
  8. ↑ Kraut JA, Madias NE. Serum anion gap: its uses and limitations in clinical medicine. Clin J Am Soc Nephrol. 2007 Jan;2(1):162-74. PubMed Abstract
  9. ↑ Payne RB, Little AJ, Williams RB, Milner JR. Interpretation of serum calcium in patients with abnormal serum proteins. Br Med J. 1973 Dec 15;4(5893):643-6. PubMed Abstract
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