Evaluate analytical method performance across screening workflows. Compare false calls, predictive values, and balanced accuracy. Use clear inputs, quick exports, and practical chemistry context.
| Assay Run | TP | TN | FP | FN | Sensitivity | Specificity |
|---|---|---|---|---|---|---|
| Screening Batch A | 48 | 90 | 10 | 2 | 96.00% | 90.00% |
| Screening Batch B | 52 | 88 | 12 | 8 | 86.67% | 88.00% |
| Confirmatory Set C | 40 | 95 | 5 | 5 | 88.89% | 95.00% |
| Confirmatory Set D | 61 | 119 | 6 | 4 | 93.85% | 95.20% |
Sensitivity = TP / (TP + FN)
Specificity = TN / (TN + FP)
Accuracy = (TP + TN) / (TP + TN + FP + FN)
Precision = TP / (TP + FP)
Negative Predictive Value = TN / (TN + FN)
Balanced Accuracy = (Sensitivity + Specificity) / 2
Youden Index = Sensitivity + Specificity - 1
Likelihood Ratio Positive = Sensitivity / (1 - Specificity)
Likelihood Ratio Negative = (1 - Sensitivity) / Specificity
Specificity and sensitivity are core measures in chemical assay validation. They show how well a method separates target and non-target samples. Sensitivity measures how often the method detects real positives. Specificity measures how often the method rejects real negatives. Both matter in screening, confirmation, and quality control.
Analytical laboratories use these metrics during method development and routine verification. A high sensitivity method reduces missed detections. That is useful in trace analysis, residue testing, and impurity checks. A high specificity method reduces false alarms. That helps when matrices are complex and interferences are common.
A confusion matrix organizes assay outcomes into true positives, true negatives, false positives, and false negatives. Those four counts support deeper performance analysis. This calculator goes beyond two basic ratios. It also reports accuracy, precision, negative predictive value, balanced accuracy, likelihood ratios, diagnostic odds ratio, F1 score, prevalence, and Matthews correlation coefficient.
No single metric tells the whole story. A method can be very sensitive but still lack specificity. That means it detects many targets but also flags clean samples. Another method can be very specific but miss low-concentration analytes. The best interpretation depends on the chemistry objective, regulatory limits, and sample matrix difficulty.
Use this calculator during validation reports, instrument comparison studies, and assay optimization work. Enter counts from reference materials, split samples, or benchmark methods. Then compare the derived metrics before choosing screening cutoffs or confirmatory criteria. Clear performance summaries support stronger technical decisions and cleaner audit documentation.
Sensitivity shows how often the method correctly detects positive samples. A high value means the assay misses fewer true target cases during chemical analysis.
Specificity shows how often the method correctly classifies negative samples. A high value means fewer false alarms from non-target compounds or interfering matrices.
False positives can trigger unnecessary retesting, rejected batches, or incorrect conclusions. They often point to poor selectivity, matrix effects, or cross-reactive compounds.
False negatives hide real target detections. In chemistry, that can mean missed contaminants, overlooked residues, or incomplete impurity control.
Use likelihood ratios when you want stronger interpretive context. They help show whether a positive or negative result meaningfully changes confidence in the assay decision.
Youden index summarizes sensitivity and specificity in one value. It is useful when comparing alternate cutoffs or competing analytical methods.
Yes. It is useful for screening methods, confirmatory methods, and validation studies. It helps compare missed detections against false alarms in one place.
MCC and F1 score add balance when classes are uneven. They help assess overall classification quality beyond simple accuracy alone.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.