Lapis ISSN 2398-2969

Urinalysis: erythrocytes

Contributor(s): Lesa Thompson, Anna Meredith, Vicki Baldrey

Overview

  • Presence of erythrocytes in urine (hematuria Urine: hematuria) occurs with various urinary or reproductive tract conditions, including inflammation, infection, calculi and neoplasia.
  • Hematuria may be seen in cases of:
    • Cystitis Cystitis, including chronic polypoid cystitis and "sludgy urine".
    • Urolithiasis Urolithiasis/hypercalciuria Urine: hypercalciuria.
    • Renal infarcts.
    • Pyelonephritis Kidney: nephritis.
    • Leptospirosis.
    • Septicemia.
    • Disseminated intravascular coagulation (DIC).
    • Abortion.
    • Endometrial hyperplasia.
    • Endometrial venous aneurysms.
    • Uterine polyps.
    • Uterine neoplasia such as uterine adenocarcinomas Uterine adenocarcinoma.
    • Rabbit hemorrhagic disease (RHD) Viral hemorrhagic disease with renal involvement and DIC will result in hematuria.
  • After treatment of small urocytoliths by urohydropropulsion, hematuria will likely be present for up to two days.

Sampling

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Tests

Methodologies

  • Chemical reagent test strip: semi-quantitative testing, result as negative or as positive in range to 1+ to 4+.
  • Microscopic examination of urine sediment:
    • To obtain sediment, centrifuge on low speed for 5 min and decant supernatant Urinalysis: centrifuged deposit. Take a drop of sediment onto a clean microscope slide and add a coverslip to examine as a wet preparation.
    • Examine under a low (x10) and high power (x40 dry): erythrocytes are seen as uniform sized pale red-brown to yellow cells, sometimes with a visible biconcave shape. Erythrocyte casts may be present from renal hemorrhage.
  • Note that porphyrin pigments from the diet, which also result in red coloration of urine, fluoresce under ultraviolet light, eg a Wood's lamp.

Availability

  • Urine test strips are cheap and readily available.
  • Equipment for microscopy includes centrifuge and light microscope; both are available in most veterinary practices.

Validity

Sensitivity

  • Good.
  • Microscopic examination of urine sediments is necessary to differentiate between hematuria and hemoglobinuria, myoglobinuria or porphyrinuria; this is important diagnostically.

Specificity

Predictive value

  • Confirmation of presence of erythrocytes is only possible using microscopy.

Technique (intrinsic) limitations

  • Equipment is required for microscopic urine examination: centrifuge to spin sample and light microscope to examine sediment.
  • Optimal sampling technique for urine analysis is cystocentesis; however, this may require sedation or anesthesia in some individuals.
  • If using a dipstick for testing, consider significance of result in conjunction with urine specific gravity as more dilute urine will affect the cellular concentration.
  • High concentrations of ascorbic acid may inhibit reagent strip reactions and reduce sensitivity of dipstick testing for blood.
  • Conversely, microscopy may give a false-negative result if erythrocytes in urine lyze before analysis. In this case, the dipstick reading will be positive (for hemoglobin).
  • Hyposthenuric urine may cause hypotonic lysis of erythrocytes, interfering with microscopic detection of the cells.
  • Reports from human medicine also suggest that captopril may decrease reactivity of dipstick reagents testing for blood.

Technician (extrinsic) limitations

  • If using a dipstick interpret test strip at specified time interval.

Result Data

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Jenkins J R (2010) Evaluation of the rabbit urinary tract. J Exotic Pet Med 19 (4), 271-279 VetMedResource.
  • Ozkan C, Kaya A & Akgul Y (2012) Normal values of haematological and some biochemical parameters in serum and urine of New Zealand White rabbits. World Rabbit Sci 20 (4), 253-259. DOI: http://dx.doi.org/10.4995/wrs.2012.1229.
  • Zadravec M, Gombac M, Racnik J, Rojs O Z, Pogacnik M & Svara T (2012) Uterine heterologous malignant mixed Mullerian tumor in a dwarf rabbit (Oryctolagus cuniculus). J Vet Diag Invest 24 (2), 418-422 PubMed.

Other sources of information

  • Varga M (2014) Urogenital Disease. In: Textbook of Rabbit Medicine. 2nd edn. Butterwoth-Heinemann, Oxford. pp 405-424.
  • Wesche P (2014) Clinical Pathology. In: Manual of Rabbit Medicine. Eds: Meredith A & Lord B. BSAVA.


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