POTASSIUM

Major intracellular cation

Potassium (K+)

is the primary cation found inside cells.

Potassium (K+)

Concentration difference

Potassium is 20 times greater inside the cell than outside.

Plasma potassium circulation

Only 2% of total body potassium is found in plasma.

Platelets

Fragments from megakaryocytes that contain potassium.

Pseudohyperkalemia

A condition that falsely elevates potassium levels in the blood.

Clumping and coagulation

These processes can release potassium, increasing serum K+ levels.

True or False?

Potassium levels in serum are higher than in plasma.

Thrombocytosis

A condition characterized by a high platelet count, which can increase potassium levels.

Heparin

Anticoagulant used for K+ collection

• Prolonged tourniquet application

• Fist Clenching (muscle activity)

Situation that can cause shifts in potassium levels.

In vitro hemolysis

Can cause a 3-30% increase in potassium levels.

Whole blood sample storage

Should be kept at room temperature.

Colorimetric methods

Lockhead and Purcell method.

Sodium potassium cobaltinitrite

A compound formed in the colorimetric reaction for potassium measurement.

Indicator electrode (ISE)

Measures the activity of potassium in a specimen.

Potentiometry

An electrochemical technique used to measure potassium levels.

Valinomycin

An antibiotic used to make ion-selective electrodes selective for potassium.

Turbidimetric method

A photometric method for measuring potassium concentration.

Wavelength for measurement

Potassium is measured at 578 nm.

Reference range for potassium

Normal potassium levels range from 3.6 to 5.5 mmol/L.

Na- Tetraphenylborate + K+ →k- Tetraphenylborate + Na+

K+ Reaction

Turbidimetric method

Method used in package insert

5 mmol/L

Potassium Standard concentration

T

Reagent and standard is ready to use

T or F?

T

sealed reagents are stable up to the expiry date

Tor F?

T

stored at 2-8c

T or F?

F

protected from the light

Should not be protected from the light

T or F?

• Once opened stable up to 4 weeks

F

Once opened stable up to 3 weeks

T or F?

• • K+ reagent

    • 1000ul

  • Standard

    • 25ul

  • Sample

    • 25ul

Volumes of the ff:

• K+ reagent

• standard

• sample

5mins @ room temp.

incubation time

14mmol/L

Linearity

10mins @ 578 nmn

Duration of test & wavelength

Normal Saline Solution

solution used in Dilution of sample

K+ conc. (mmol/L) = Ab sample / Ab Standard x5

Formula for K+ conc.