Comprehensive Metabolic Panel (CMP) Reference Chart for Psychiatric Practice

Component	Reference Range	Psychiatric Relevance	Clinical Flags
Sodium (Na+) mmol/L	136 - 145	Hyponatremia (<135): Common with SSRIs, carbamazepine, oxcarbazepine SIADH Risk: Monitor closely in elderly patients on antidepressants Symptoms: Confusion, headache, seizures, altered mental status	SSRI Risk Carbamazepine
Potassium (K+) mmol/L	3.5 - 5.1	Hypokalemia: May occur with eating disorders, diuretics, or lithium Hyperkalemia: ACE inhibitors, potassium-sparing diuretics ECG Changes: Monitor for cardiac conduction abnormalities	Eating Disorders Lithium
Chloride (Cl-) mmol/L	98 - 107	Hyperchloremia: Salicylate intoxication, decreased water intake Hypochloremia: Water intoxication, overuse of antacids Clinical Context: Usually parallels sodium changes	Electrolyte Panel
CO2 (Bicarbonate) mmol/L	20 - 31	Low CO2: Eating disorders (purging), alcoholism, ketosis High CO2: Head injury, liver disease, dehydration Acid-Base Status: Essential for metabolic acidosis/alkalosis evaluation	Eating Disorders Alcohol Use
Glucose mg/dL	70 - 99 (≥15 years) 65 - 99 (29 days-14 years) 40 - 99 (0-28 days)	Hyperglycemia: Atypical antipsychotics, treatment with glucocorticoids Hypoglycemia: Insulin overdose, anorexia nervosa, alcohol use Metabolic Syndrome: Monitor with olanzapine, clozapine, quetiapine Delirium Risk: Both high and low glucose can precipitate altered mental status	Antipsychotics Anorexia
BUN mg/dL	9 - 23	Elevated BUN: Renal failure, dehydration, lithium toxicity Low BUN: Malnutrition, liver disease, overhydration Psychiatric Symptoms: Uremia can cause delirium, confusion	Lithium Delirium
Creatinine mg/dL	Male: 0.70 - 1.30 Female: 0.55 - 1.02	Elevated Creatinine: Lithium nephrotoxicity, dehydration Drug Clearance: Affects elimination of renally cleared medications Monitoring: Essential for lithium, duloxetine, gabapentin dosing	Lithium Duloxetine
Calcium mg/dL	8.3 - 10.6	Hypocalcemia: Chronic alcohol use, vitamin D deficiency, anticonvulsants Hypercalcemia: Lithium therapy, laxative abuse Symptoms: Mood changes, confusion, muscle weakness	Alcohol Use Anticonvulsants
Albumin g/dL	3.4 - 5.0	Low Albumin: Increases free drug concentrations Clinical Impact: Risk of toxicity at "therapeutic" total drug levels Causes: Liver dysfunction, malnutrition, chronic illness Action: Consider free drug level monitoring when albumin <3.0 g/dL	Free Drug Levels Protein Binding
Total Protein g/dL	5.7 - 8.2	Low Protein: Malnutrition, liver disease, chronic illness High Protein: Dehydration, multiple myeloma Psychiatric Relevance: Affects drug protein binding	Nutrition Status
Globulin g/dL	2.7 - 4.3	Calculated: Total Protein - Albumin Elevated: Chronic inflammation, infection, liver disease Low: Immunodeficiency, malnutrition	Immune Status
Alkaline Phosphatase U/L	46 - 116	Elevated ALP: Cholestatic liver injury from medications Cholestatic Pattern: ALP >3× ULN with normal/minimally elevated ALT/AST Medications: Phenothiazines, tricyclics, benzodiazepines	Cholestatic Injury Drug Reaction
ALT U/L	9 - 40	Hepatocellular Injury: ALT more specific for liver damage than AST Hy's Law: ALT ≥3× ULN + bilirubin ≥2× ULN = hepatotoxicity Medications: Valproate, carbamazepine, antipsychotics	Hy's Law Hepatotoxicity
AST U/L	13 - 40	Less Specific: Found in liver, heart, muscle, kidneys AST/ALT Ratio: >2 suggests alcohol-related liver damage Hy's Law: AST ≥3× ULN + bilirubin ≥2× ULN = hepatotoxicity	Hy's Law Alcohol Use
Total Bilirubin mg/dL	0 - 1.0 (≥28 days) 0 - 11.7 (0-28 days)	Elevated Bilirubin: Liver dysfunction, hemolysis, drug reactions Hy's Law Component: Bilirubin ≥2× ULN indicates severe hepatotoxicity Medications: Chlorpromazine, phenothiazines, haloperidol	Hy's Law Drug Reaction
Anion Gap mmol/L	7 - 16	Formula: (Na + K) - (Cl + CO2) High Anion Gap: Diabetic ketoacidosis, alcohol poisoning, salicylate Normal Gap Acidosis: Diarrhea, ureterosigmoidostomy	Acid-Base Metabolic Status
BUN/Creatinine Ratio	10 - 20	High Ratio (>20): Dehydration, GI bleeding, high protein intake Low Ratio (<10): Low protein intake, liver disease Clinical Use: Helps differentiate prerenal vs. intrinsic renal disease	Renal Function

🧠 Psychiatric Practice Applications

The CMP provides essential information for psychiatric medication management, metabolic monitoring, and identification of medical conditions that may present with psychiatric symptoms. The enhanced psychiatric interpretations below are based on evidence-based clinical practice guidelines.

🔴 High-Risk Medications

Lithium: Monitor creatinine, BUN, sodium (nephrotoxicity risk)
Valproate: Monitor ALT, AST (hepatotoxicity risk)
Carbamazepine: Monitor sodium (SIADH risk), liver enzymes
Atypical Antipsychotics: Monitor glucose (metabolic syndrome)

🟡 Moderate-Risk Medications

SSRIs: Monitor sodium (hyponatremia risk, especially elderly)
Duloxetine: Monitor creatinine (renal impairment affects dosing)
Tricyclics: Monitor liver enzymes, electrolytes
MAOIs: Monitor glucose, liver function

🔵 Baseline Monitoring

Hospital Admission: Complete CMP for baseline assessment
Mental Status Changes: Rule out metabolic causes
New Medication: Establish pre-treatment values
Routine Follow-up: Monitor for adverse effects

Clinical Pearl: Patterns of abnormalities can suggest specific conditions. For example, low albumin + elevated transaminases suggests liver disease; low calcium + low albumin + low protein may indicate covert alcoholism.

🚨 Hy's Law Criteria for Drug-Induced Liver Injury

All three criteria must be met:

AST or ALT ≥ 3 times the upper limit of normal (≥120 U/L)
Total bilirubin ≥ 2 times the upper limit of normal (≥2.0 mg/dL)
No elevation in alkaline phosphatase (and no other reason for liver injury)

Action: When Hy's Law criteria are met, suspect hepatotoxic drug reaction. Consider immediate discontinuation of offending medication and hepatology consultation.

⚠️ Cholestatic Drug Reaction Pattern

Suspect cholestatic injury when:

Alkaline phosphatase > 3 times the upper limit of normal (>348 U/L)
AST and ALT levels normal or only minimally elevated

Common Offenders: Phenothiazines, tricyclic antidepressants, chlorpromazine, benzodiazepines

📊 Toxicity Monitoring Schedule

Medication	Baseline CMP	Follow-up Frequency	Key Parameters
Lithium	Required	Every 6 months (stable); every 3 months (elderly)	Creatinine, BUN, Sodium
Valproate	Required	Baseline, 2 weeks, 1 month, then every 6 months	ALT, AST, Total Bilirubin
Carbamazepine	Required	Baseline, 2 weeks, then every 3-6 months	Sodium, ALT, AST
Atypical Antipsychotics	Required	Baseline, 3 months, then annually	Glucose (fasting preferred)

🔍 Red Flag Combinations

Sodium <130 + New SSRI: Possible SIADH, especially in elderly
Creatinine doubling + Lithium: Nephrotoxicity, consider dose reduction
Glucose >200 + Atypical antipsychotic: Screen for diabetes
ALT >3× + Any new medication: Potential hepatotoxicity

🧪 Free vs. Total Drug Level Considerations

When albumin levels are low, the unbound (free) percentage of highly protein-bound psychotropics increases, potentially leading to toxicity at apparently therapeutic total drug levels. Free drug levels provide more accurate assessment of pharmacologically active drug concentrations.

High Protein Binding (>90%)

Valproic Acid: 88-95% bound
Phenytoin: 90-95% bound
Carbamazepine: 75-85% bound
Diazepam: 95-99% bound

Action: Consider free levels when albumin <3.0 g/dL

Moderate Protein Binding (50-90%)

Quetiapine: 83% bound
Risperidone: 90% bound
Sertraline: 98% bound
Paroxetine: 95% bound

Action: Monitor for increased side effects if albumin low

Low Protein Binding (<50%)

Lithium: No significant binding
Gabapentin: <3% bound
Topiramate: 13-17% bound
Lamotrigine: 55% bound

Action: Total levels remain accurate regardless of albumin

📋 When to Order Free Drug Levels

Clinical Scenario	Indication	Recommended Action
Albumin <3.0 g/dL	Decreased protein binding	Order free levels for highly bound drugs
Pregnancy	Altered protein binding	Consider free levels, especially phenytoin
Renal Failure	Uremic toxins compete for binding	Free levels more accurate
Liver Disease	Decreased albumin synthesis	Monitor albumin; consider free levels
Toxicity at "Therapeutic" Levels	Possible increased free fraction	Check albumin; order free level

Important: Free drug levels are available for many psychotropics but may require special handling and longer turnaround times. Consult your laboratory for specific requirements and availability.

References

American Psychiatric Association. (2020). Practice guideline for the treatment of patients with schizophrenia (3rd ed.).
Hiemke, C., et al. (2018). AGNP consensus guidelines for therapeutic drug monitoring in psychiatry: Update 2017. Pharmacopsychiatry, 51(1-2), 9-62.
Jacobson, S. A. (2017). Which metabolic panel for psychiatric practice: Basic or comprehensive? Psychiatric News, 52(1). https://doi.org/10.1176/appi.pn.2017.4a31

Note: Reference intervals may vary by laboratory. Always consult your local laboratory's established ranges for clinical decision-making. This chart provides commonly used reference intervals and should not replace clinical judgment or laboratory guidelines.

Disclaimer:

The information provided in this Comprehensive Metabolic Panel (CMP) Reference Tool is intended solely for educational and informational purposes. It does not constitute medical advice, diagnosis, or treatment, nor does it establish a provider-patient relationship. While efforts have been made to ensure the accuracy and clinical relevance of the content, PsychConcierge PLLC and PsychConcierge.com make no warranties, express or implied, regarding the completeness, reliability, or applicability of the information presented. Users are strongly encouraged to consult their licensed healthcare provider or local clinical laboratory for interpretation of laboratory values and individualized medical decisions. Reference ranges may vary by laboratory and patient population. PsychConcierge PLLC assumes no responsibility for any outcomes arising from reliance on this tool.