Which statement best describes a Class A balance?

Which statement best describes a Class A balance?

• A. A digital electronic scale with 0.01 mg readability
• B. A torsion balance required by law to be available in every pharmacy with a sensitivity of 6 mg, capable of weighing 120 mg to 155 g
• C. A spring scale used for kitchen weighings
• D. A balance used only for teaching labs

Answer: (B)

Class A balances are highly precise torsion balances used in pharmacies for accurate weighing of small quantities during compounding. They are required by law to be available in every pharmacy, ensuring that ingredients can be weighed accurately and consistently for safe, reproducible preparations. Key features include a sensitivity of about 6 mg, which means the balance can detect very small changes in mass, and a weighing range roughly from 120 mg up to 155 g, covering common compounding needs from tiny doses to larger quantities. A digital electronic scale, while capable of precise measurements, does not meet the traditional torsion-balance design and regulatory requirements of Class A. A spring scale is not precise enough for pharmaceutical work, and a balance intended only for teaching labs does not fulfill the regulatory role in an active pharmacy.

Class A balances are highly precise torsion balances used in pharmacies for accurate weighing of small quantities during compounding. They are required by law to be available in every pharmacy, ensuring that ingredients can be weighed accurately and consistently for safe, reproducible preparations. Key features include a sensitivity of about 6 mg, which means the balance can detect very small changes in mass, and a weighing range roughly from 120 mg up to 155 g, covering common compounding needs from tiny doses to larger quantities. A digital electronic scale, while capable of precise measurements, does not meet the traditional torsion-balance design and regulatory requirements of Class A. A spring scale is not precise enough for pharmaceutical work, and a balance intended only for teaching labs does not fulfill the regulatory role in an active pharmacy.