BMP & Electrolytes: Common reference range & NOTES

Question 1

Calcium, total (Ca)

Answer 1

8.5 - 10.5 mg/dL

NOTE:

• Calculate corrected calcium if albumin is low
• INCREASED due to supplementation, vitamin D, thiazide diuretics
• DECREASED due to systemic steroids, long-term heparin, loop diuretics, bisphosphonates, cinacalcet, calcitonin, foscarnet, topiramate.

Question 2

Magnesium (Mg)

Answer 2

1.3 - 2.1 mEq/L

NOTE:

• INCREASED due to magnesium-containing antacids and laxatives with renal impairment
• DECREASED due to PPIs, diuretics, amphotericin, foscarnet, echinocandins, diarrhea, chronic alcohol intake

Question 3

Phosphate (PO4)

Answer 3

2.3 - 4.7 mg/dL

NOTE:

• INCREASED in renal failure
• DECREASED due to phosphate binders, foscarnet, oral calcium intake

Question 4

Potassium (K)

Answer 4

3.5 - 5 mEq/L

NOTE:

• INCREASED due to ACEi, ARBs, aldosterone receptor antagonists, aliskiren, canagliflozin, cyclosporine, tacrolimus, potassium supplements, sulfamethoxazole/trimethoprim, drospirenone-containing OC
• DECREASED due to steroids, beta-2-agonists, conivaptan, diuretics, insulin,

Question 5

Sodium (Na)

Answer 5

135-145 mEq/L

NOTE:

• INCREASED due to hypertonic saline
• DECREASED due to carbamazepine, oxcarbazepine, SSRIs, diuretics, desmopressin

Question 6

Bicarbonate (HCO3)

Answer 6

Venous: 24-30 mEq/L
Arterial: 22-26 mEq/L

NOTE:

• used to assess acid-base status
• INCREASED due to loop diuretics, systemic steroids
• DECREASED due to topiramate, zonisamide, salicylate overdose

Question 7

Blood Urea Nitrogen (BUN

Answer 7

7-20 mg/dL

NOTE:
-INCREASED due to renal impairment and dehydration

Question 8

Serum Creatinine (SCr)

Answer 8

0.6 - 1.3 mg/dL

NOTE:

• INCREASED due to many drugs that impair renal function (aminoglycosides, amphotericin B, cisplatin, colistimethate, cyclosporine, loop diuretics, polymixin, NSAIDs, radiocontrast dye, tacrolimus, vancomycin)
• False INCREASE due to sulfamethoxazole/trimethoprim, H2RAs, cobicistat
• DECREASED with low muscle mass, amputation, hemodilution

Question 9

Anion Gap (AG)

Answer 9

5-12 mEq/L

NOTE:

• calculated value, but often reported in the BMP
• Presence of INCREASED anion gap suggests metabolic acidosis