Line 6: |
Line 6: |
| | | |
| =DIAGNOSIS= | | =DIAGNOSIS= |
− | * Laboratory testing cannot distinguish between asymptomatic colonization and active infection. | + | * Laboratory testing cannot always distinguish between asymptomatic colonization and active infection. |
| ==Diagnostic criteria== | | ==Diagnostic criteria== |
| * Diarrhea | | * Diarrhea |
| * Positive stool test for toxigenic C. diff or toxins or visualization of pseudomembranous colitis | | * Positive stool test for toxigenic C. diff or toxins or visualization of pseudomembranous colitis |
| ==Diagnostic approaches== | | ==Diagnostic approaches== |
− | * Toxigenic Culture (TC) and/or Cell Cytotoxicity Assay (CCA) | + | * Gold Standard: Toxigenic Culture (TC) and/or Cell Cytotoxicity Assay (CCA) |
| ** Anaerobic culture for 24-48 hrs followed by colony selection and culture with human cells to test for cell cytotoxicity which takes an additional 24-48 hours. | | ** Anaerobic culture for 24-48 hrs followed by colony selection and culture with human cells to test for cell cytotoxicity which takes an additional 24-48 hours. |
− | * Gold standard
| |
| ** Time consuming and difficult, up to 5 days | | ** Time consuming and difficult, up to 5 days |
| ** Detects a little as 3 picograms of toxin | | ** Detects a little as 3 picograms of toxin |
Line 21: |
Line 20: |
| * PCR / NAAT | | * PCR / NAAT |
| ** Detects tcdA/tcdB genes, mRNA for the toxins | | ** Detects tcdA/tcdB genes, mRNA for the toxins |
− | *** Detects presence of toxigenic strains of C. diff
| + | ** Detects presence of toxigenic strains of C. diff |
− | * mRNA doesn't necessarily imply active infection | + | ** mRNA doesn't necessarily imply active infection |
− | ** EIA / ELISA
| + | * EIA / ELISA |
− | *** Detects toxin in stool
| + | ** Detects toxin in stool |
− | *** Low sensitivity (0.73-0.87)
| + | ** Low sensitivity (0.73-0.87) |
| * Multistep algorithms, there are dozens | | * Multistep algorithms, there are dozens |
| ** EIA for GDH / Toxin A/B | | ** EIA for GDH / Toxin A/B |
− | * Both positive = C. diff | + | *** Both positive = C. diff |
− | * Both negative = NO C. diff | + | *** Both negative = NO C. diff |
− | * Mixed results, use PCR for tcdB as tiebreaker | + | *** Mixed results, use PCR for tcdB as tiebreaker |
| ** Toxin EIA 1 (Meridian), higher PPV, lower NPV | | ** Toxin EIA 1 (Meridian), higher PPV, lower NPV |
| ** Toxin EIA 2 (TechLab), lower PPV, higher NPV | | ** Toxin EIA 2 (TechLab), lower PPV, higher NPV |
− | * Highest NPV (99.8%) GDH EIA + NAAT | + | ** Highest NPV (99.8%) GDH EIA + NAAT |
− | * Highest PPV (93.5%) Toxin EIA 1 + NAAT | + | ** Highest PPV (93.5%) Toxin EIA 1 + NAAT |
| | | |
| =TREATMENT= | | =TREATMENT= |