Electrolytes

Question 1

Chloride (Cl-)

Answer 1

95–105 mg/dL (95–105 mmol/L)

Cl- is the main anion in the extracellular space and is the counterpart to the main extracellular cation Na+.

Cl- is involved in water balance, maintaining osmotic pressure, and acid-base balance.

Question 2

Magnesium (Mg2+)

Answer 2

1.5–2.0 mg/dL (0.75–1.0 mmol/L)

Part of bone matrix
Mg2+ is one of the main intracellular cations.

Question 3

Phosphate (H2PO4-, HPO42-)

Answer 3

3.0–4.5 mg/dL (1.0–1.5 mmol/L)

Approx. 85% of the body’s phosphate is found in the bone matrix.

Question 4

Lactic acid (lactate)

Answer 4

< 2.0 mmol/L

Lactic acid is the end product of anaerobic glycolysis, which is accomplished in the Cori cycle.
The majority of lactic acid is produced by muscle cells and RBCs, especially in hypoxic states. 
Hyperlactatemia
Common causes
Tissue hypoperfusion (hypoxic states)
Heart failure
Sepsis and other infections
Shock
Infarction
Lung disease (e.g., pulmonary embolism)
Dehydration
Severe anemia and pancytopenia
Poisoning
CO (carbon monoxide)
Ethanol
Methanol
Ethylene glycol
Liver disease 
Drugs (e.g., metformin or isoniazid)