Urinalysis Review and Case Studies

Transcription

1 Urinalysis Review and Case Studies A Complete Urinalysis John H. Landis, MS, MLS(ASCP) Adjunct Professor, University of Cincinnati Adjunct Professor, Oakland University Professor Emeritus, Ferris State University Meglumine Waxy Cast p Three Parts Physical Examination n Chemical Examination n Microscopic Examination Omitted in some laboratories if the physical and chemical exams are normal n Uric Acid Drugs Causing Color Change in Urine 5 6 1

2 Common Causes of Cloudiness in Urine Chemical Examination by Reagent Strips p Principles of tests differ depending on the reagent strip brand: n Multistix by Siemens n Chemstrip by Roche p Many similarities; a few important differences p Reagent strip readers standardize color interpretation 7 8 Correlations Between Exams serve as limited QC checks Correlation between Chemical and Microscopic Exams p Physical and Chemical Exams n Color with SG, blood, or bilirubin Example: red color expect positive blood p Physical and Microscopic Exams n Clarity with amount of microscopic entities Example: cloudy urine expect significant number of microscopic entities 9 10 Chemical Examination: Reagent Strip Tests Case # 1 Age: 40 Sex: M Clinical Info: ED, severe back and abdominal pain; CBC and Amylase normal p (SG) p ph p Blood (heme) p Protein (albumin) p Leukocyte Esterase p Nitrite screening tests p Glucose p Ketone p Bilirubin p Urobilinogen indicate metabolic disorder Color Yellow Glucose Neg Clinitest Appearance Hazy Protein Trace SSA: Ketones Neg ph 5.0 Bilirubin Neg Ictotest: Blood 2+ Urobilinogen Normal Nitrite Neg Leuk Est Neg 11 Microscopic : 0-5 WBCs/hpf ; 10-25???? /hpf; unidentified crystals present 12 2

3 Case # 1 Case # Calcium Oxalate monohydrate Calcium oxalate - dihydrate Red compensated Polarized light Case # 1 p What abnormal findings are present: n p 2+ Blood and RBCs/hpf What are causes of the findings: n Bleeding in the genitourinary tract p Trauma, Calcium oxalate monohydrate 17 inflammation, calculi, tumors p Why are the RBCs so weird looking? n Crenated due to the high Sp. Gr. p Why CBC and Amylase? n Doc is checking for appendicitis and pancreatitis 18 3

4 Chemical Exam: Blood (heme) Hgb H 2 O 2 + Chromogen* Oxidized + H 2 O chromogen Mgb *tetramethylbenzidine Renal Calculi 19 Hgb = Hemoglobin Mgb = Myoglobin 20 Chemical Exam: Blood (heme) NOTE p Principle: pseudoperoxidase activity of the heme moiety p Equally detects: hemoglobin, myoglobin p Chemstrip results are not affected by ascorbic acid interference due to an iodate scavenger pad that overlays test pad p Other brands can give a false negative or lower result if ascorbic acid is present ( 9 mg/dl) If microscopic examination is NOT performed, microscopic hematuria can be missed when ascorbic acid is present Why? Ascorbic acid reduces the H 2 O 2 on the reaction pad, preventing oxidation of the chromogen by any heme present Undetected Microscopic Hematuria If RBCs present, but reagent strip Blood test is negative p Retrospective study* of 709 consecutive urine specimens p Microscopic hematuria was present in 204 specimens (29%) p Chemical test for blood was negative in 21% (43/204) of these samples p If only the reagent strip blood test is used, microscopic hematuria can be missed. *Brunzel NA, Berry DE. Omitting the microscopic examination of urine: what is missed? 23 Abstract MP10.45, IFCC-FESCC European Congress, May 2005 p Check for ascorbic acid (Chemstrip not affected); report accordingly p Retest specimen for blood using well-mixed, unspun urine p Ensure no sample mix-up has occurred between phys/chem and micro exam p Re-evaluate identity: n Are the RBCs really crystals? Check using polarizing microscopy. n Are the RBCs really yeast? Stain. 24 4

5 Case # 2 Age: 56 Sex: F Clinical Info: Urology clinic for intravenous pyelogram Color Yellow Glucose Neg Clinitest Appearance Hazy Protein Trace SSA: 4+ >1.035 Ketones Neg ph 6.0 Bilirubin Neg Ictotest: Blood Neg Urobilinogen Normal Nitrite Neg Leuk Est Neg Microscopic : 0-5 WBCs/hpf ; Unidentified crystals present Case # Case #

6 Case # 2 Case # 2 p What are the abnormal findings: n n 4+ SSA n Unidentified Crystals p Possible causes of abnormals: n Tech Error on Sp. Gr. n Crystals - Drugs p Discrepancies n Trace protein, but 4+ SSA p Causes of Discrepancies n Radiographic dye is not detectable by strip p Accurate n New specimen or Use Strip Sp. Gr. p Crystals??? n Radiographic contrast dye crystals Case # 3 Age: 13 Sex: M Clinical Info: Severe back and abdominal pain; both father and uncle are kidney stone formers Case # 3 Color Yellow Glucose Neg Clinitest Appearance Hazy Protein Trace SSA: Ketones Neg ph 6.0 Bilirubin Neg Ictotest: Blood 2+ Urobilinogen Normal Nitrite Neg Leuk Est Neg Microscopic : 0-5 WBCs/hpf ; ????? /hpf; Unidentified crystals present Case # 3 Case # 3 p Abnormal findings: n Blood - pad and RBCs n Cystine crystals Polarizing filter p Cause of Abnormals: n Damage (kidney to urethra) trauma, infection, tumor, calculi p Physiologic Abnormality n Cystinuria Defective reabsorption of Amino Acids Inherited ; usually shows age 20-30s

7 Case # 3 Case # 4 Age: 14 Sex: M Clinical Info: 3 wks prior sore throat with Positive culture for b hemolytic strep. Now weakness, Anorexia, headache and puffy eyelids. Oliguria present p Additional AA found in the urine in cystinuria n Leucine, ornithine and arginine p Cystinosis n Inherited metabolic disorder with intracellular deposition of cystine in all cells n Particular damage to the kidney, eye, marrow and spleen n Evident within first year of life Color Red- Brown Glucose Neg Clinitest Appearance Cloudy Protein 300mg/dL SSA: 3+ mg/dl Ketones Neg ph 6.0 Bilirubin Neg Ictotest: Blood 3+ Urobilinogen Normal Nitrite Neg Leuk Est Neg 37 Microscopic : 0-5 WBCs/hpf ; 10-25????? /hpf; 0-5????? /lpf (2 types) 38 Case # 4 Case # Case # 1 Case # 4 p Abnormal findings & Discrepancies n Red-Brown, Cloudy, Large Blood Protein, RBCs, RBC casts, Hemoglobin casts p Morphology of RBCs n Dysmorphic RBCs Dysmorphic RBCs Glomerular or tubular bleeding 41 p Likely Diagnosis? n Post-streptococcal Acute Glomerulonephritis 42 7

8 Case # 5 Age: 7 Sex: F Clinical Info: History of recent infections. Facial and general edema; urine pale and there is white foam Case # 5 Color Straw Glucose Neg Clinitest Appearance Hazy Protein >2000 > mg/dl Ketones Neg SSA: 4+ ph 6.0 Bilirubin Neg Ictotest: Blood Neg Urobilinogen Normal Oil Red O Stain Nitrite Neg Leuk Est Neg Microscopic : 0-5 WBCs/hpf ; 0-5????? /hpf; 0-5????? /lpf (2 types) Case # 5 Case # Case # 5 p Abnormal findings: n Oval fat bodies n Protein n Fatty casts n Hyaline casts p White foam? n Albumin p Edema? n Hypoproteinemia p Diagnosis? n Nephrotic Syndrome Protein Reagent Strip Test Protein error of indicators Indicator + Protein dye ph 3 H+ released from indicator (blue-green)

9 Protein Reagent Strip Test Microscopic Evidence of Fat p Essentially specific for albumin; more sensitive to it than any other protein (e.g., hemoglobin, myoglobin, mucoproteins, immunoglobulin light chains) p Note that the amount of blood/hemoglobin in urine must be greater than 5-10 mg/dl (> Large) before the protein test detects it [Blood pad detection limit: 0.02 mg/dl] p Free floating fat globules p Fat in cells (RTEs, WBCs, macrophages), called oval fat bodies (OFB) p Fat in casts, called fatty casts Fat should be confirmed before reporting p Polarizing microscopy n cholesterol forms characteristic maltese cross pattern n triglyceride/neutral fat does NOT polarize p Fat stains (Sudan III, Oil Red O) n triglyceride/neutral fat stains characteristic orange (or terra-cotta) color n cholesterol does NOT stain

10 55 56 Urinary Fat (Lipiduria) p Fat is always clinically significant p Check for fat when protein is ~300 mg/dl or greater using either n polarizing microscopy n fat stains Always Correlate Exams serves as a limited QC check Chemical and Microscopic Exams p If fat present, then albumin (protein) must be present. p If no albumin (protein) (and/or other pathology), suspect specimen is contaminated with lotions, salves, etc In Summary p Any condition/disease that alters the selectivity (pore size) of the GFB (glomerular filtration barrier) can result in proteinuria and, if severe enough, lipiduria n Renal disease n Metabolic disease n Conditions that cause blood pressure changes Case # 6 Color Yellow Glucose Neg Clinitest Appearance Hazy Protein 300 mg/dl Age: 65 Sex: M Clinical Info: Diabetes (Type 1) with oliguria Ketones Neg SSA: ph 6.0 Bilirubin Neg Ictotest: Blood Neg Urobilinogen Normal Nitrite Neg Leuk Est Neg 59 Microscopic : 0-5 WBCs/hpf ; 5-10????? /lpf; 60 10

11 Case # 6 Case # Case # 6 Case # 7 Age: 48 Sex: F Clinical Info: Emergency appendectomy with bleeding; transfused with 1 unit packed cells; 2 hrs later developed fever, chills, 2 days later UA and Rous test p Abnormal results n Protein n Broad and Waxy Casts p Confirmatory Microscopy n Waxy casts will not light up with Polarized light p Cause of abnormal results n Chronic Renal Failure p Why Broad and Waxy Casts? n Dilation of tubules and formation in the collecting ducts Color Brown Glucose Neg Clinitest Appearance Sl Cloudy Protein 300 mg/dl Ketones Neg SSA: ph 5.0 Bilirubin Neg Ictotest: Blood 3+ Urobilinogen 4 E.U./L Rous Test: Nitrite Neg Leuk Est Neg Positive 63 Microscopic : 0-5 WBCs/hpf ; 0-5 RBCs/hpf; 2-5???? /hpf 64 Case # 7 Case # 7 Unstained Iron Stain Unstained Iron Stain

12 Case # 7 Case # 7 p Abnormal findings & Discrepancies: n Brown, Sl cloudy, 3+ blood, protein, n Urobilinogen, Rous test, Unidentified objects p Discrepancy: n Blood on pad but no RBCs p Cause of discrepancy n Intravascular hemolysis Hemoglobinuria or myoglobin p Hemosiderin? n Storage form of iron; iron entered renal tubular cells and renal cells died p Brown color of urine? n Methemoglobin or urobilin p Why urobilinogen? n Increased available in small intestine for reabsorption because of hemolytic event p No urine Bilirubin? n Only conjugated bilirubin in urine n Unconjugated bound to albumin and not filtered by glomeruli Case # 8 Age: 32 Sex: M Clinical Info: Sinus infection treated with methicilin; patient developed severe edema Case # 8 Physician ordered a Hansel Stain on the sediment Color Yellow Glucose Neg Clinitest Appearance Cloudy Protein 300 mg/dl Ketones Neg SSA: ph 6.0 Bilirubin Neg Ictotest: Hansel Stain Blood 2+ Urobilinogen Normal Nitrite Neg Leuk Est Pos Microscopic : RBCs/hpf ; >100????/hpf; 0-5???? /lpf Case # 8 Case # 8 p Abnormal findings & Discrepancies n Cloudy, Blood, Protein, Leuk Esterase, WBCs, Eosinophils, WBC casts p Technique for Hansel stain n Centrifuge or cytocentrifuge the urine stain sediment with Wright s or Hansel s stain p Cause of Abnormal results? n Inflammatory reaction - interstitial nephritis

13 Case # 9 Age: 65 Sex: M Clinical Info: Construction worker admitted because of a fall and overnight his urine output drops while on IV fluids. Case # 9 Color Brown Glucose Neg Clinitest Appearance Hazy Protein 300 mg/dl Ketones Neg ph 6.0 Bilirubin Neg Ictotest: SSA: 1+ Blood 3+ Urobilinogen Normal Nitrite Neg Leuk Est Neg Microscopic : 0-5 RBCs/hpf ; 0-5????/hpf; 10-25???? /lpf Epithelial Cells Epithelial Cells Renal epithelial cells Case # 9 p Abnormal findings: n Color, Appearance, blood, protein, Renal tubular epithelial cells, hyaline casts p Discrepancies: n Blood on pad but no RBCs p Cause of discrepancies? n Hemoglobinuria or myoglobinuria

14 Case # 9 Case # 10 Age: 8 months Sex: M Clinical Info: Failure to thrive; Slow motor development; appearance of orange sand in diapers p Further testing? n Screen for Hgb vs Myoglobin n CK and LD; visual of plasma p Probable diagnosis? n Rhabdomyolysis with acute renal failure Color Yellow Glucose Neg Clinitest Appearance Hazy Protein Neg SSA: Ketones Neg ph 5.0 Bilirubin Neg Ictotest: Blood Neg Urobilinogen Normal Nitrite Neg Leuk Est Neg 79 Microscopic : 0-5 WBCs/hpf ;???? crystals 80 Case # 10 Case # Case # 10 Case # 10 p Abnormal findings? n Uric Acid crystals p ph consistent? n Yes, Uric acid seen in acid urine p Diagnosis? n Lesch-Nyhan disease n sex-linked recessive n Uric acid accumulation

15 Facts about Urine Crystals Why dont I ever see these crystals? p When solutes exceed their solubility, they can precipitate in various forms crystalline or amorphous p Factors contributing to crystal formation: n Solute concentration n ph n Temperature n Urine flow Bilirubin crystals Cholesterol crystals Leucine crystals Tyrosine crystals Today, rapid turn-around-times as well as reduced refrigeration of specimens prevents their precipitation What is the ph? ACID ( 7.0) p ph 5.7: think uric acid n yellow to brown n variety of shapes & sizes p ph > 5.7: think urates n amorphous urates granular material n monosodium urates thin, colorless needles n urate salts (K +, NH 4+ ) brown spheres & clusters n add glacial acetic acid will convert to uric acid

16 What is the ph? ALKALINE (> 7.0) p Think phosphates n n n n Amorphous PO4-2 fine, granular material Triple phosphates colorless, 3 to 6 sided prisms Calcium phosphates p colorless, thin prisms with one tapered end; forms rosettes or stellar patterns p colorless, thin sheets with irregular edges Ammonium biurate yellow-brown spheres 91 Triple phosphate Calcium Phosphates Triple phosphate Ammonium biurate

17 Many crystals present? Physiologically Possible ph p ph p Suspect medication or dietary supplement/excess with inadequate hydration n Check medications and recent procedures (e.g., radiographic, imaging) n Evaluate patient history p If ph < 4.5 or ph > 8.0, indicates: n iatrogenically induced (e.g., medication, IV imaging media) ph > 8.0; ammonium biurate crystals can be present in fresh, normal urine n improper storage/handling References p Brunzel, N.A., Fundamentals of Urine and Body Fluid Analysis, Saunders, p Haber, et.al., Color Atlas of Urinary Sediment, CAP Press, p Strasinger, S, Urinalysis and Body Fluids, F.A. Davis, 2007 p Simerville, J., et. al., Urinalysis: A Comprehensive Review, American Family Physician, March 15, 2005, p landisj@gmail.com 99 17