Chemistry Electrolytes + Kidney

Creatinine Range in Serum/Plasma

0.8-1.2 mg/dL. 71-106 umol/L. Too high means abnormal renal function

Cystatin C

Inversely correlated w GFR. Freely filtered but almost completely reabsorbed

Urea

Metabolic product of protein catabolism. 90% excreted. BUN. Decreased in starvation or end stage liver disease

BUN Serum Range

6-20 mg/dL, 2.1-7.1 mmol/L

BUN/Creatinine Ratio (10:1) Increase

Renal hypoperfusion, catabolic states of tissue breakdown, high protein intake, Postrenal azotemia

BUN/Creatinine Ratio Decrease

Acute tubular necrosis, low protein intake, starvation, severe liver disease

Uric Acid Decreased

Less than 2 mg/dL. Severe liver disease or defective renal tubular reabsorption

Osmotic pressure

Pressure that opposes osmosis as a solvent flows through a semipermeable membrane. More solutes, increased osmotic pressure

Sodium Plasma Range

136-145 mmol/L

Potassium K+

Contraction of cardiac, skeletal and smooth muscle. Excreted by kidneys. ISE or spectrophotometry. No hemolysis in samples!

Potassium Plasma Range

3.5-5.1 mmol/L

Chloride Cl-

Major extracellular anion. Reabsorbed. Anion-cation balance, water distribution and osmotic pressure. ISE or coulometric-amperometric titration

Chloride plasma range

98-107 mmol/L

Bicarbonate serum range

23-29 mmol/L

Calcium Ca2+

Most prevalent cation in body. Muscle contraction cofactor, hormone secretion, glycogen metabolism, cell division, blood clotting.

Calcium States

Ionized/Free: bioactive for total calcium. Protein-Bound: to albumin or globulins. Complexed: biologically active. Total calcium is ionized + bound.

Total calcium methods

Photometry, atomic absorption spectrometry. Serum or heparin used plasma. No hemolysis, EDTA, citrate or oxalate

Buffers

Weak acid and its conjugate base

Amperometry

Magnitude of current flowing through circuit is proportional to species being reduced

Arterial pH

7.35-7.45

Arterial pCO2

35-44 mmHg, 4.7-5.9 kPa

Arterial pO2

Over 80mmHg, over 10.6 kPa

Hypokalemia

Muscle weakness, irritability, paralysis, tachycardia, cardiac conduction deficits, cardiac arrest

Hyperkalemia

Disorientation, weakness, tingling, flaccid paralysis of extremities, weakness of respiratory muscles, bradycardia, cardiac conduction issues. Can be from redistribution, increased intake or increased retention.

Hypochloremia

Acidosis. More bicarbonate.

Hyperchloremia

Dehydration, prolonged diarrhea. Respiratory alkalosis. Low bicarbonate, CO2

Hypocalcemia

Neuromuscular and cardiac symptoms. Hypoalbuminemia, hypoparathyroidism.

Hypocalcemia

Neuromuscular and cardiac symptoms.

Glucose Plasma Range

74-100 mg/dL, 4.1-5.6 mmol/L

Glucose CSF Range

50-80 mg/dL, 2.8-4.4 mmol/L

Pyruvate Specimen

4 hour fast + rest. Whole blood. Prechill

Hgb A1C Range

Less than 5.7%, 39 mmol/mol