Urinalysis 1 Urinalysis Urinalysis Intervention White blood cells seen under a microscope from a urine sample. MeSH D016482 [1] A urinalysis (or "UA") is an array of tests performed on urine and one of the most common methods of medical diagnosis. [2] A part of a urinalysis can be performed by using urine dipsticks, in which the test results can be read as color changes. Examples of tests In addition to the substances mentioned in tables below, other tests include: • a des cri pti on of c olor and a ppeara nce . • Icotes t - The test use d to detect th e destru ction of ol d Red Bloo d Cells (RB C) in the urin e. • Hemog lobin Tes t - Hemolys is in the blood vess els, a ruptur e in the capilla ries of the glomerulu s, or hemorrh age in the urinary system may cause hemoglobin to appear in the urine. • hCG - normal ly absent , this hormo ne appea rs in the urine of pregn ant wome n. Home preg nancy tes ts commonly detect this substance. Ions and trace metals Target Lower limit Upper limit Unit Comments Nitrite n/a 0 /negative [3] The presence of nitrites in urine indicate the presence of coliform bacteria. This may be a sign ofinfection, however, the other parameters such as leukocyte esterase, urine white blood cell count, and symptoms such as dysuria, urgency, fevers and chills must be correlated to diagnose an infection. Sodium (Na) - per day 150 [4] 300 [4] mmol /24hours The sodium levels are frequently ordered during the workup of acute renal f ailure. The fractional excretion of sodium, abbreviated as FeNa is an important marker in distinguishin g pre-renal from post-renal failure. Potassium (K) - per day 40 [4] 90 [4] mmol /24hours Urine potassium may be ordered in the workup of hypokalemia. In case of GI loss of potassium, the urine potassium will be low. In case of renal loss of potassium, the urine potassium levels will be high. Decreased levels of urine potassium are also seen in hypoaldosteronism and adrenal insufficiency.
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Phosphaturia is the hyperexcretion of phosphate in the urine. This condition is divided into
primary and secondary types. Primary hypophosphatemia is characterized by direct excess
excretion of phosphate by the kidneys, as from primary renal dysfunction, and also the direct
action of many classes of diuretics on the kidneys. Additionally, secondary causes, including bothtypes of hyperparathyroidism cause hyperexcretion of phosphate in the urine.
A sodium-related parameter is fractional sodium excretion, which is the percentage of the sodium filtered by the
kidney which is excreted in the urine. It is a useful parameter in acute renal failure and oliguria, with a value below
1% indicating a prerenal disease and a value above 3%[5]
indicating acute tubular necrosis or other kidney damage.
Proteins
Target
Lower
limit
Upper
limit
Unit Comments
Protein 0trace
amounts[3]
/ 20
mg/dL Proteins may be measured with the Albustix Test. Since proteins are very large molecules
(macromolecules), they are not normally present in measurable amounts in the glomerular filtrate or in the
urine. The detection of protein in urine, called proteinuria may indicate that the permeability of the
glomerulus is abnormally increased. This may be caused by renal infections or it may be caused by other
diseases that have secondarily affected the kidneys such as diabetes mellitus, jaundice, or
hyperthyroidism.
Blood cells
Target Lowerlimit
Upperlimit
Unit Comments
Red blood
cells (RBCs) /
erythrocytes
0[3]
[6]
2[3]
- 3[6] per
High
Power
Field
(HPF)RBC casts n/a
0 /
negative[3]
White blood
cells (WBCs)
/
leukocytes
0[3]
2[3]
/
negative[3]
WBC in urine are a marker of infection if present for greater than 5 wbc per high power field
Significant pyuria at greater than or equal to 10 leucocytes/microl {cubic millimeter}.
Blood n/a0 /
negative[3]
May be present as intact RBC which indicates bleeding or discoloration. Note that a very small
amount of blood is enough to give the entire urine sample or the foley bag a red/pink hue, and it is
difficult to judge the amount of bleeding from a gross examination. The urine color may also be
red due to excretion of pigment such as myoglobin and hemoglobin, in which case the urine
dipstick shows presence of blood but there are no RBC seen on microscopic examination. Always
check INR/PT/PTT and send a fresh urine sample for urinalysis when blood is detected. A case
can also be made for urine cytology, especially for elderly patients.