Loop Calibration Checkers

Cat. no. 7020 , CalCheck™, 1ul For use with 1ul loops (0.001ml)
Cat. no. 3830 , without handle, platinum, 1ul, 26 gauge
Cat. no. 3630 , without handle, nichrome, 1ul, 26 gauge
Cat. no. 3730 , with handle, nichrome, 1ul, 26 gauge
Cat. no. 7010 , CalCheck™, 10ul For use with 10ul loops (0.01ml)
Cat. no. 3640 , without handle, nichrome, 10ul, 26 gauge
Cat. no. 3740 , with handle, nichrome, 10ul, 26 gauge


CalCheck™ is used to check the calibration of wire inoculation loops. Nichrome V loops calibrated to deliver 0.001ml (1ul) and 0.01ml (10ul) are used to inoculate culture media with liquid specimens when colony counts are required. The loops are composed of 26 gauge twisted nichrome wire. Although applicable to nearly any liquid or specimen, this inoculation method is most frequently used when urine is submitted for bacterial culture. Calibration of the loop volume is based on the thickness of the wire and circumference of the loop.

The CalCheck™ is a loop calibration checker that uses two stainless steel posts to measure tolerances of plus or minus 0.001 inch. The diameters of the posts are as follows:

CalCheck™ for 1ul Cat. no. 7020
Green post = 0.0550 inch Red post = 0.0595 inch
CalCheck™ for 10ul Cat. no. 7010
Green post = 0.157 inch Red post = 0.159 inch

The procedure below describes an easy and rapid method to verify the calibration of these loops using the CalCheck™.


Daily: The delivery volume of calibrated loops may change due to damage, corrosion, or build-up of incinerated material. It should be visually inspected to confirm that the loop is still round and the circle has not parted.

Weekly: To verify that the loops have maintained their proper size, insert the end of the 0.001ml loop through the green end of the calibrated gauge (Cat. no. 7020). A 0.001ml loop of proper size fits over the green side of gauge, but not over the red side of gauge. Follow the same procedure for the 0.01ml calibrated loop, using the 0.01ml calibrated gauge (Cat. no. 7010).

Warning: The CalCheck™ is designed to calibrate only 26-gauge wire. The inside diameter of the loops made with 29-gauge wire is too large to be used with the CalCheck™. The nichrome loops now provided by Hardy Diagnostics are made only of 26-gauge nichrome wire. Please use the CalCheck™ with the above listed calibrated loops.


1. Barry, A.L., B.B. Smith, M. Turck and T.L. Gavin. 1975. Laboratory Diagnosis of Urinary Tract Infections , CUMITECH 2; American Society for Microbiology; Washington, D.C.

2. Standard Methods for the Examination of Dairy Products , 12th ed. 1967, 14th ed., 1978. American Public Health Association, Washington, D.C.