1 / 10

Chemical Examination of Urine Part IV: Nitrite & Leukocyte Esterase

Chemical Examination of Urine Part IV: Nitrite & Leukocyte Esterase. Ricki Otten MT(ASCP)SC uotten@unmc.edu. Nitrite: Purpose. Bacteria that contain a specific enzyme can reduce dietary nitrates to nitrites Rapid screening test for UTI. Nitrite: Normal. Normal: negative Abnormal:

colby-riley
Download Presentation

Chemical Examination of Urine Part IV: Nitrite & Leukocyte Esterase

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Chemical Examination of UrinePart IV:Nitrite & Leukocyte Esterase Ricki Otten MT(ASCP)SC uotten@unmc.edu

  2. Nitrite: Purpose • Bacteria that contain a specific enzyme can reduce dietary nitrates to nitrites • Rapid screening test for UTI

  3. Nitrite: Normal • Normal: negative • Abnormal: • Cystitis: bladder • Pyelonephritis: kidney

  4. Nitrite: Method • Reagent strip test Nitrite + aromatic amine  diazonium salt Diazonium salt + aromatic compound  pink color • Sensitivity: 0.06-0.1 mg/dl nitrite ~ 10,000 organisms

  5. Nitrite: Method • Reagent strip test Specificity: • False positive: improper specimen handling; color masking • False negative: bacteria cannot reduce nitrates Bladder time not sufficient: need 4 hours Low nitrite levels Ascorbic acid Antibiotic inhibition of bacteria Further reduction of nitrites to nitrogen

  6. Leukocyte Esterase: Purpose • Increased WBC in urine is pathologic • Indicates inflammation, infection • Neutrophils most common type of WBC found in urine • Can detect intact WBC and lysed WBC

  7. Leukocyte Esterase: Normal • Normal: negative • Abnormal: • Bacterial infection: cystitis, pyelonephritis, urethritis • Non-bacterial infection: yeast, trichomonas

  8. Leukocyte Esterase: Method • Reagent strip: Granules in cytoplasm of WBC contain an enzyme (esterase) Ester –esterase aromatic compound Aromatic compound + diazonium salt  Purple colored complex

  9. Leukocyte Esterase • Sensitivity: 5-15 WBC/hpf • Specificity: • False positive: vaginal contamination; color masking • False negative: strong oxidizing agents (bleach); lymphocytes (no granules)

More Related