Interpretation of UAs

Interpretation of UAs

TEST                                       INTERPRETATION

Proteinuria                    A urine dip will detect only albumin, not nonalbumin proteins such as globulins and Bence Jones proteins; there must be at least 100–150 mg protein/dL (equivalent to ∼ 300 mg protein/day) for  the dip to become pos. A UA will detect albumin and nonalbumin proteins, but there must be at least 1–10 mg protein/dL for the UA to be pos.

Glucosuria                    Indicates the possibility of hyperglycemia.

Ketonuria                     Occurs with starvation, uncontrolled diabetes, and alcohol intoxication as well as post exercise and during pregnancy.

Hematuria                    Will become _ when myoglobin, hemoglobin, or RBCs are present in the urine.

Nitrite                          Can become _ with gram-negative bacteriuria.

Leukocyte esterase      Produced by WBCs in urine and suggestive of UTI.

pH                              Alkalosis: Proteus in UTI; some strains of Klebsiella, Pseudomonas, Providencia, and Staphylococcus.

Acidosis with nephrolithiasis suggests uric acid or cystine stones. Failure to acidify < pH 5.5 in the setting of metabolic acidosis suggests distal renal tubular acidosis (RTA).

Specific gravity            A rough estimate of urine osmolarity (Uosm).

Urobilinogen                urobilinogen indicates hemolysis or hepatocellular disease. ↓ urobilinogen indicates biliary obstruction.

Bilirubin                       Bilirubin in the urine suggests a conjugated hyperbilirubinemia.

Epithelial                      An excessive number of epithelial cells in the urine suggests a contaminated urine sample.

Urine Sediment

FINDING                                              ASSOCIATION

Hyaline casts                Normal finding, but an ↑ amount suggests a prerenal condition.

RBC casts                   Glomerulonephritis.

WBC casts                  Pyelonephritis.

Eosinophils                  Allergic interstitial nephritis.

Glomerular, “muddy    Acute tubular necrosis (ATN).

brown” casts

RBCs                         Indicates hematuria.

WBCs                        Indicates injury to the body or urinary tract. Can be caused by infection, nephrolithiasis, neoplasm, acute interstitial cystitis, acute interstitial nephritis, strictures, and glomerulonephropathy.

Crystals                      nephrolithiasis.

Yeast, bacteria           Indicates infection if the sample is not contaminated (e.g., epithelial cells).