Analyze test outcomes with flexible confusion matrix inputs. Inspect rates, ratios, and predictive values instantly. Export results fast for audits, reports, and method checks.
| Example Assay | TP | FP | FN | TN | Sensitivity | Specificity |
|---|---|---|---|---|---|---|
| Residue Screen Panel | 86 | 9 | 14 | 91 | 86.00% | 91.00% |
| Contaminant Marker Test | 72 | 11 | 8 | 109 | 90.00% | 90.83% |
Chemistry labs often classify samples as positive or negative. That choice may depend on a signal cutoff, an instrumental response, or a screening threshold. Sensitivity shows how well the method detects real positives. Specificity shows how well it rejects real negatives. Together, these values describe analytical discrimination. They also show whether a method is better for screening or better for confirmation. A clear balance can reduce retesting, wasted reagents, and reporting delays.
A sensitivity specificity table starts with four counts. True positives and true negatives represent correct decisions. False positives and false negatives represent analytical risk. In chemistry, that risk can affect safety, cost, and compliance. A false positive may trigger extra review, extra standards, and extra instrument time. A false negative may miss contamination, residues, or unstable compounds. This calculator converts those raw counts into practical metrics for method review.
Method validation needs more than one headline number. Accuracy, predictive value, and likelihood ratios add context. Precision helps you understand how often positive calls are reliable. Negative predictive value helps you judge negative results. Balanced accuracy supports uneven class distributions. Youden index helps compare cutoffs. Matthews correlation coefficient gives a compact summary when classes are imbalanced. These values help scientists compare thresholds, tune screening rules, and document assay performance in validation reports.
Predictive values depend on prevalence, so they can change across sample sets. That is why sensitivity and specificity should be reviewed beside PPV and NPV. A chemistry team may use one threshold for broad screening and another for confirmation. This page makes that review easier. It organizes the confusion matrix, core formulas, advanced ratios, and exportable output in one place. That supports quality assurance, analytical development, and routine laboratory communication.
A sensitivity specificity table is a confusion matrix. It stores true positives, false positives, false negatives, and true negatives. From those four counts, you can calculate sensitivity, specificity, accuracy, predictive values, and several advanced performance indicators.
Chemistry methods often classify samples around a decision threshold. This tool helps evaluate screening assays, residue tests, contaminant detection methods, and validation studies. It shows whether a method detects positives well and rejects negatives reliably.
High sensitivity means the method captures most real positives. It keeps false negatives low. This is often important in early screening, contamination review, and situations where missing a positive sample creates more risk than extra follow-up testing.
High specificity means the method correctly rejects most true negatives. It keeps false positives low. This is useful when unnecessary confirmations, extra reagent use, or incorrect positive flags would create avoidable laboratory cost and effort.
Yes. PPV and NPV depend on prevalence. If positive samples become more common, PPV can rise. If positive samples become rare, NPV can rise. That is why predictive values should be interpreted with the sample population in mind.
Zero counts are possible. Some metrics can still be calculated, but others may become undefined or infinite. This calculator shows N/A or Infinity where appropriate, which helps you identify limit cases during assay review.
Yes. Balanced accuracy averages sensitivity and specificity. It can be more informative than plain accuracy when positive and negative classes are not evenly distributed. That makes it useful for many laboratory screening and validation datasets.
Yes. The calculator is useful for validation summaries, assay comparisons, cutoff reviews, and internal quality documents. The CSV and PDF options also make it easier to move results into audit files, reports, and method review records.
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.