Urine test: Difference between revisions

The value of urine for diagnostic purposes has been recognized since ancient times. Urine examination was practiced in [[Sumer]] and [[Babylonia]] as early as 4000 BC, and is described in ancient [[Ancient Greek|Greek]] and [[Sanskrit]] texts.<ref name="ki2">{{cite journal |last vauthors = Armstrong JA |first=J.A.| title = Urinalysis in Western culture: a brief history | journal = Kidney International Reports|date=2007| volume = 71 | issue = 5 | pages =384-7 384–387 | date = March 2007 | pmid = 17191081 | doi = 10.1038/sj.ki.5002057 | doi-access = free }}</ref> Contemporary urine testing uses a range of methods to investigate the physical and biochemical properties of the urine. For instance, the results of the routine [[urinalysis]] can provide information about the functioning of the [[kidneys]] and [[urinary system]]; suggest the presence of a [[urinary tract infection]] (UTI); and [[Screening (medicine)|screen]] for possible [[diabetes]] or [[liver disease]], among other conditions.<ref name="statpearls"/> A [[urine culture]] can be performed to identify the bacterial species involved in a UTI.{{sfn|Turgeon|2016|p=505}} Simple [[point-of-care test]]s can detect [[pregnancy]] by identifying the presence of [[beta-hCG]] in the urine{{sfn|Turgeon|2016|p=216}} and indicate the use of [[recreational drugs]] by [[Urine drug screen|detecting excreted drugs or their metabolites]].<ref name="mayo">{{cite journal |last vauthors = Moeller|first=K.E.|last2= KE, Kissack|first2=J.C.|last3= JC, Atayee|first3=R.S.|last4= RS, Lee KC |first4=K.C.|date=2017| title = Clinical Interpretation of Urine Drug Tests: What Clinicians Need to Know About Urine Drug Screens | journal =[[ Mayo Clinic Proceedings]] | volume = 92 | issue = 5 | pages = 774–796 | date = May 2017 | pmid = 28325505 | doi = 10.1016/j.mayocp.2016.12.007 | s2cid = 21260113 | doi-access = free }}</ref> Analysis of abnormal cells in urine ([[urine cytology]]) can help to diagnose some [[cancer]]s,{{sfn|McPherson|Pincus|2017|p=479}} and testing for [[Urine organic acids|organic acids]] or [[Aminoaciduria|amino acids]] in urine can be used to screen for some [[genetic disorder]]s.{{sfn|Rifai|Horvath|Wittwer|2018|p=1697}}

The techniques used to collect urine specimens vary based on the desired test. A random urine, meaning a specimen that is collected at any time, can be used for many tests. However, a sample collected during the first urination of the morning (first morning specimen) is preferred for tests like urinalysis and pregnancy screening because it is typically more concentrated, making the test more [[Sensitivity and specificity|sensitive]].{{sfn|Brunzel|2018|pp=19–22}}{{sfn|Mundt|Shanahan|2016|p=264}} Because the concentration of many substances in the urine varies throughout the day, some tests require timed urine collections, in which the patient collects all of their urine into a container for a given period of time (commonly 24 hours). A small amount of the specimen is then removed for testing. Timed collections are commonly used to measure [[Urine creatinine|creatinine]], [[urea]], [[urine protein]], [[hormones]] and [[electrolytes]].{{sfn|Brunzel|2018|pp=19–22}}{{sfn|Mundt|Shanahan|2016|pp=75–6}}

If urine is needed for [[microbiological culture]], it is important that the sample is not contaminated. In this case, the proper collection procedure involves cleaning the genital area, beginning to urinate into the toilet, and then filling the specimen container before completing the urination into the toilet. This is called a "midstream clean catch" collection.{{sfn|Brunzel|2018|pp=19–22}} Research has shown many women are unsure of how to take a midstream sample or why it is needed.<ref>{{cite journal |date=11 December 2022 |title=Do women know how to take a urine sample? |url=https://evidence.nihr.ac.uk/alert/do-women-know-how-to-take-a-urine-sample/ |journal=NIHR Evidence}}</ref> <ref>{{cite journal | vauthors = Glogowska M, Croxson C, Hayward G | title = Women's information needs around urine testing for urinary tract infections: a qualitative study | journal = The British Journal of General Practice | volume = 72 | issue = 717 | pages = e244–e251 | date = April 2022 | pmid = 35190371 | pmc = 8869185 | doi = 10.3399/BJGP.2021.0564 }}</ref>

If the subject is not able to urinate voluntarily, samples can be obtained using a [[urinary catheter]] or by inserting a needle through the abdomen and into the bladder ([[suprapubic aspiration]]).<ref name="statpearls">{{cite webjournal|last vauthors = Queremel Milani|first2= DA|last2=, Jialal|first= I |title=Urinalysis|date=8 May 2022|workjournal=StatPearls|pmid=32491617 |url=https://www.ncbi.nlm.nih.gov/books/NBK557685/|accessdateaccess-date=13 July 2022|archive-date=5 April 2022|archive-url= https://web.archive.org/web/20220405015846/https://www.ncbi.nlm.nih.gov/books/NBK557685/|url-status=live}}</ref> In infants and young children, urine can be collected into a bag attached to the genital region, but this is associated with a high risk of contamination.{{sfn|Brunzel|2018|pp=19–22}}

*[[Urine electrolyte levels]] — measurement of [[electrolytes]] such as [[sodium]] and [[potassium]] in urine<ref name="wu">{{cite journal |first vauthors = Wu X.|last=Wu | title = Urinalysis: Aa Reviewreview of Methodsmethods and Proceduresprocedures | journal = Critical Care Nursing Clinics of North America | volume = 22 | issue = 1 | pages = 121–128 | date = March 2010 | pmid = 20193886 | doi = 10.1016/j.ccell.2009.10.012 }}</ref>

*[[Urine cytology]] — [[cytopathological]] examination of cells in the urine, used to screen for cancer<ref name="xing">{{cite journal |last vauthors = Xing|first= J.|last2=, Reynolds JP |first2=J.P.|date=2018| title = Diagnostic Advances in Urine Cytology | journal = Surgical Pathology Clinics | volume = 11 | issue = 3 | pages =601-610 601–610 |journal date =Surgical PathologySeptember 2018 Clinics| pmid = 30190143 | doi = 10.1016/j.path.2018.06.001 | s2cid = 52171396 }}</ref>

* {{cite book | vauthors = Brunzel NA |title=Fundamentals of Urine and Body Fluid Analysis|last=Brunzel|first=N.A.|date=2018|publisher=[[Elsevier]]|edition=44th|isbn=978-0-323-37479-8|url=https://books.google.cacom/books?id=_D5yDQAAQBAJ}}

* {{cite book|last1 vauthors = McPherson|first1=R.A.|last2= RA, Pincus|first2=M.R. MR |title=Henry's Clinical Diagnosis and Management by Laboratory Methods|url=https://books.google.com/books?id=xAzhCwAAQBAJ|year=2017|publisher=Elsevier Health Sciences|isbn=978-0-323-41315-2|edition=23}}

* {{cite book | vauthors = Mundt LA, Shanahan K |title=Graff's Textbook of Urinalysis and Body Fluids|edition=3|last1=Mundt|first1=L.A.|last2=Shanahan|first2=K.|date=2016|ISBNisbn=978-1-4963-2016-2|publisher=[[Wolters Kluwer]]}}

* {{cite book|last vauthors = Reddi|first=A.S. AS |title=Fluid, electrolyte, and acid-base disorders: clinical evaluation and management|date=2014|publisher=[[Springer (publisher)|Springer]]|isbn=978-1-4614-9082-1|pages=13−4|url=https://wwwbooks.google.cacom/books/edition/Fluid_Electrolyte_and_Acid_Base_Disorder/kC3ABAAAQBAJ?hlid=en&gbpv=1kC3ABAAAQBAJ&dq=978-1-4614-9082-1&pg=PP1&printsec=frontcover}}

* {{cite book | vauthors = Rifai N, Horvath AR, Wittwer CT |title=Tietz Textbook of Clinical Chemistry and Molecular Diagnostics|last1=Rifai|first1=N.|last2=Horvath|first2=A.R.|last3=Wittwer|first3=C.T.|edition=66th |publisher=Elsevier|date=2018|isbn=978-0-323-35921-4|url=https://books.google.cacom/books?id=3mRgDwAAQBAJ}}

* {{cite book|last vauthors = Turgeon|first= ML |title=Linné & Ringsrud's Clinical Laboratory Science: Concepts, Procedures, and Clinical Applications|url=https://books.google.com/books?id=QyvRoQEACAAJ|year=2016|publisher=Elsevier Mosby|isbn=978-0-323-22545-8|edition=7}}