The most direct, simple, and accurate method for estimating leanness-fatness is measuring the thickness of skinfolds by constant-tension calipers. The Lange Skinfold Calipers manufactured by Beta Technology Inc., are specifically designed for the simple, accurate measurement of subcutaneous tissue.

The Lange Caliper incorporates the recommended principles for standardized usage in nutrition, fat distribution, child growth, anthropomorphic studies, and other applications.

Pivoted tips adjust automatically for parallel measurement of skinfolds, and rectangular faces with well-rounded edges and corners assure patient comfort. The face area is approximately 30 square mm. An easy-to-read scale permits reading up to 60 mm. Accurate to +/- 1 mm. Spring-loaded levers provide a substantially constant standard pressure of 10 gm./sq. mm. over the entire operating range. All critical pivot points utilize low friction bearings to maintain accurate tip pressure at all jaw openings. The caliper is of sturdy, light-weight construction, and is anti-corrosive. Each unit is supplied in an individual case.

It is important to use calipers in which the pressure is built into the instrument itself and is relatively constant from reading to reading and over the range of skinfold thickness studied. Early models of calipers were unsatisfactory in that spring-loaded tension was very low at small openings but increased rapidly as the jaws of the calipers were opened.

Experience has shown that caliper pressure of about 10 gm./sq. mm. is preferable to a very low or very high pressure and that it be constant over a range of openings from two to at least 40 mm. For the purposes of standardization, this pressure that has been recommended irrespective of the design of the caliper itself, with a contact surface from 20-40 sq. mm., depending on the shape of the surface.

Data obtained with skinfold calipers has been found to agree with measurements obtained from roentgenograms of soft tissues. In turn, these determinations of subcutaneous fat have been correlated with calculations of total body fat obtained by other methods.

Skinfold measurements, especially when combined with limb circumferences, permit finer discrimination between soft tissue sites than is possible from inspection. Such discrimination is advantageous in diagnosing individual nutritional status.