Editing Proteinuria (section)

==Diagnosis==
{|class="wikitable" align="right"
!colspan=3| Protein dipstick grading
|-
!rowspan=2| Designation !! colspan=2| Approx. amount
|-
| Concentration<ref>{{EMedicine|article|984289|Pediatric Proteinuria}}</ref> || Daily<ref>{{cite journal |vauthors=Ivanyi B, Kemeny E, Szederkenyi E, Marofka F, Szenohradszky P | title = The value of electron microscopy in the diagnosis of chronic renal allograft rejection | journal = Mod. Pathol. | volume = 14 | issue = 12 | pages = 1200–8 | date = December 2001 | pmid = 11743041 | doi = 10.1038/modpathol.3880461 | doi-access = free }}</ref>
|-
| Trace || 5–20&nbsp;mg/dL ||
|-
| 1+ || 30&nbsp;mg/dL || Less than 0.5 g/day
|-
| 2+ || 100&nbsp;mg/dL || 0.5–1 g/day
|-
| 3+ || 300&nbsp;mg/dL || 1–2 g/day
|-
| 4+ || More than 1000&nbsp;mg/dL || More than 2 g/day
|}
Conventionally, proteinuria is diagnosed by a simple [[Urine test strip|dipstick test]], although it is possible for the test to give a false negative reading,<ref name="pmid15791892">{{cite journal |last1=Simerville |first1=Jeff A. |last2=Maxted |first2=William C. |last3=Pahira |first3=John J. |title=Urinalysis: a comprehensive review |journal=American Family Physician |date=15 March 2005 |volume=71 |issue=6 |pages=1153–1162 |id={{ProQuest|234160912}} |pmid=15791892 |url=https://www.aafp.org/link_out?pmid=15791892 }}</ref> even with nephrotic range proteinuria if the urine is dilute.<ref>{{cite book |doi=10.1016/B978-0-323-04107-2.50126-5 |chapter=Proteinuria |title=Decision Making in Medicine |date=2010 |pages=358–361 |isbn=978-0-323-04107-2 | vauthors = Worobey CC, Singh AK }}</ref> False negatives may also occur if the protein in the urine is composed mainly of [[globulin]]s or [[Bence Jones proteins]] because the reagent on the test strips, [[bromophenol blue]], is highly specific for albumin.<ref name="pmid15791892"/><ref>{{cite web |url=http://medlib.med.utah.edu/WebPath/TUTORIAL/URINE/URINE.html |title=Urinalysis |access-date=6 August 2006 |url-status=dead |archive-url=https://web.archive.org/web/20060810213920/http://medlib.med.utah.edu/WebPath/TUTORIAL/URINE/URINE.html |archive-date=10 August 2006 }} Retrieved 20 January 2007</ref> Traditionally, dipstick protein tests would be quantified by measuring the total quantity of protein in a 24-hour urine collection test, and abnormal globulins by specific requests for [[protein electrophoresis]].<ref name=friedlander />{{Better source needed|date=April 2025}}<ref>{{cite web |url=http://www.answers.com/topic/protein-electrophoresis |title=Answers - the Most Trusted Place for Answering Life's Questions |website=[[Answers.com]] |access-date=6 August 2006 |url-status=live |archive-url=https://web.archive.org/web/20070212061659/http://www.answers.com/topic/protein-electrophoresis |archive-date=12 February 2007 }} Retrieved 20 January 2007</ref>

More recently developed technology detects [[human serum albumin]] (HSA) through the use of [[liquid crystal]]s (LCs). The presence of HSA molecules disrupts the LCs supported on the AHSA-decorated slides thereby producing bright optical signals which are easily distinguishable. Using this assay, concentrations of HSA as low as 15&nbsp;μg/mL can be detected.<ref name="Aliño">{{cite journal |vauthors=Aliño VJ, Yang KL | title = Using liquid crystals as a readout system in urinary albumin assays. | journal = Analyst | volume = 136 | issue = 16 | pages = 3307–13 | year = 2011 | pmid = 21709868 | doi = 10.1039/c1an15143f | bibcode = 2011Ana...136.3307A }}</ref>

Alternatively, the concentration of protein in the urine may be compared to the [[creatinine]] level in a spot urine sample. This is termed the protein/creatinine ratio. The 2005 UK Chronic Kidney Disease guidelines state that protein/creatinine ratio is a better test than 24-hour urinary protein measurement. Proteinuria is defined as a protein/creatinine ratio greater than 45&nbsp;mg/mmol (which is equivalent to [[Microalbuminuria|albumin/creatinine ratio]] of greater than 30&nbsp;mg/mmol or approximately 300&nbsp;mg/g) with very high levels of proteinuria having a ratio greater than 100&nbsp;mg/mmol.<ref>{{cite web |title=Identification, management and referral of adults with chronic kidney disease: concise guidelines |url=http://www.renal.org/CKDguide/full/Conciseguid141205.pdf |date=27 September 2005 |publisher=UK Renal Association |url-status=dead |archive-url=https://web.archive.org/web/20130219152620/http://www.renal.org/CKDguide/full/Conciseguid141205.pdf |archive-date=19 February 2013 }} – see Guideline 4 Confirmation of proteinuria, on page 9</ref>

Protein dipstick measurements should not be confused with the amount of protein detected on a test for [[microalbuminuria]] which denotes values for protein for urine in mg/day versus urine protein dipstick values which denote values for protein in mg/dL. That is, there is a basal level of proteinuria that can occur below 30&nbsp;mg/day which is considered non-pathology. Values between 30 and 300&nbsp;mg/day are termed [[microalbuminuria]] which is considered pathologic.<ref>{{cite journal|title=Urinary dipstick protein: a poor predictor of absent or severe proteinuria.|journal=Am J Obstet Gynecol |pmid=8296815|volume=170|issue=1 Pt 1 |date=Jan 1994|pages=137–41|doi=10.1016/s0002-9378(94)70398-1|vauthors=Meyer NL, Mercer BM, Friedman SA, Sibai BM }}</ref> Urine protein lab values for microalbumin of >30&nbsp;mg/day correspond to a detection level within the "trace" to "1+" range of a urine dipstick protein assay.  Therefore, positive indication of any protein detected on a urine dipstick assay obviates any need to perform a urine microalbumin test as the upper limit for microalbuminuria has already been exceeded.<ref>{{cite web|title=The Urine Dipstick|url=http://www.georgiahealth.edu/alliedhealth/pa/documents/ClinicianReviewsCC.UrineDipstick.Gunder.pdf|publisher=Georgia Regents University|url-status=dead|archive-url=https://web.archive.org/web/20130616063747/http://www.georgiahealth.edu/alliedhealth/pa/documents/ClinicianReviewsCC.UrineDipstick.Gunder.pdf|archive-date=16 June 2013}}</ref>

===Analysis===
It is possible to analyze urine samples in determining [[albumin]], [[hemoglobin]] and [[myoglobin]] with an optimized [[Micellar electrokinetic chromatography|MEKC]] method.<ref>{{cite journal |vauthors=Kočevar Glavač N, Injac R, Kreft S | year = 2009 | title = Optimization and Validation of a Capillary MEKC Method for Determination of Proteins in Urine | journal = Chromatographia | volume = 70 | issue = 9–10| pages = 1473–1478 | doi = 10.1365/s10337-009-1317-3 }}</ref>