What method measures refractive index to determine solute concentration in serum?

What method measures refractive index to determine solute concentration in serum?

• A. Refractometry
• B. Spectrometry
• C. Turbidimetry
• D. Centrifugation

Answer: (A)

Measuring how light bends in a liquid reveals how much dissolved material is present. In serum, the refractive index increases with solute concentration, so a refractometer can translate that index into an estimate of total dissolved solids or total protein. This method is quick, requires only a small sample, and is commonly used for fast assessments. Temperature matters because refractive index changes with temperature, so readings are made at a standard temperature or with temperature compensation. The other methods focus on different properties: spectrometry relies on light absorption by specific substances, turbidimetry measures cloudiness from suspended particles, and centrifugation separates components by spinning.

Measuring how light bends in a liquid reveals how much dissolved material is present. In serum, the refractive index increases with solute concentration, so a refractometer can translate that index into an estimate of total dissolved solids or total protein. This method is quick, requires only a small sample, and is commonly used for fast assessments. Temperature matters because refractive index changes with temperature, so readings are made at a standard temperature or with temperature compensation. The other methods focus on different properties: spectrometry relies on light absorption by specific substances, turbidimetry measures cloudiness from suspended particles, and centrifugation separates components by spinning.