On the downside, the procedure is highly operator dependent, requires special training by a pathologist and is associated with an appreciable false-negative rate
Because the subdermal lymphatics are partially obstructed, contain tumour emboli, and are functionally abnormal, the false-negative rate
for SLNB in this population may be unacceptably high .
TABLE 4 Niton Soil Measurement Methods and Corresponding False-Negative Rates
Niton Soil Number of Number of Measurement False-Negative Positive Laboratory Method Readings (<400 ppm) Results ([greater than or equal to]400 ppm) Surface readings 13 62 (Test Cup 2) Bagged readings 13 62 (Test Cup 2) Test Cup 1 1 57 (Test Cup 1) (prepared by grinding) Test Cup 2 2 62 (Test Cup 2) (prepared by grinding and sieving) Niton Soil False-Negative Measurement Rate Method Surface readings 21% Bagged readings 21% Test Cup 1 2% (prepared by grinding) Test Cup 2 3% (prepared by grinding and sieving)
We accepted a false-negative rate
of less than 5%, as recommended by the consensus group, and accepted a manual review rate of less than 30%, according to our capacity for smear review and the average review rate of the CAP survey.
A false-negative rate
of 23% on a single lateral view of the cervical spine was reported by Bachulis et al.
The false-negative rate
can be reduced by serial sectioning to reduce sampling error and rapid IHC for epithelial markers but producing a reliable result within an intraoperative time (usually approximately 40 minutes), often on multiple SLNs, can cause logistical problems.
The false-negative rate
, based on 5 women out of 422, is 1.
The clinical false-negative rate
of the SLNB in this study was 0%.
Figure 1 shows that four quantitative characteristics [sensitivity (Se), specificity (Sp), positive predictive value (PPV), and negative predictive value (NPV)] are defined by two properties of the screening method (the false-positive rate, or, and the false-negative rate
, [3) and by a property of the danger being assessed, the frequency of true hazards, P[H], where H is a true hazard.
But the Pap test is only a screening tool, with a false-negative rate
of from 10 to 20 percent in the best laboratories -- meaning that the test fails to detect uterine or cervical cancer 10 to 20 percent of the time.
Jackson also reported that with the IEC, ADA, and VA/DoD cutoffs for diabetes, screening with HbA1C was specific but insensitive, with a false-negative rate
of 68% at the 6.
Troponin testing, for example, has proven valuable because its false-negative rate