Urine Dipstick (Full Ward Test, FWT)

Last updated 20.09.12

 

Definition

-  Use of chemical reagent disptick to assess urine

 

Features

-  Rapid ward/office based Ix of urine

-  Also referred to as a Full Ward Test (FWT)

-  If abnormality detected often sent for MCS

 

Indication

-  Investigation of abdominal pain

-  UTI

-  Urolithiasis

-  DKA

-  Pregnancy

-  Antenatal screening for asymptomatic bacteruria

-  UTI

-  GDM

-  Renal impairment (ARF, CRF)

-  DM

 

Equipment

-  Non-sterile gloves

-  Paper towel

-  Urine specimen container

-  Chemical reagent strips (Dipsticks)

 

Procedure

-  Collection of urine

-  MSU, SPA or fresh catheter (IDC, in-out) samples best

-  Examine urine specimen

-  Color: haematuria, concentrated, myoglobinuria, bile

-  Clarity: cloudy (proteinuria, UTI)

-  Odour: UTI, DM

-  Immerse dipstick completely in fresh urine & remove immediately

-  Remove excess urine

-  Run test strip along edge of urine specimen container

-  Then blot side of dipstick on paper towel

-  Hold dipstick horizontally to prevent running of chemicals

-  Wait for 1 minute

-  Hold dipstick against container to read levels

-  Ensure correct orientation

 

Dipstick

 

Results

-  Specific Gravity (SG)

-  <1.008: dilute

-  >1.020: concentrated

-  pH

-  N: 4.5-8

-  <4.5: diet, uric acid calculi, RTA

-  >8: RTA, infection, stag-horn calculi (urolithiasis)

-  Blood

-  +: Haematuria, haemoglobinuria, myoglobinuria

-   Detects haemoglobin

-   Urine MCS to confirm

-  False +ve: menstruation, dehydration, exercise

-  Fale -ve: Captopril, Vit C, proteinuria, increased SG, pH <5.1, bacteriuria

-  Protein

-  +: Proteinuria

-   Will not pick up Bence Jones proteins

-  Protein-Creatinie ratio or 24hr urine protein to confirm

-  Fale -ve: alkaline or dilute urine

-  Glucose

-  +: Glucosuria: DM

-  False +ve: ketonuria (high levels), Levodopa

-  False –ve: elevated SG, uricosuria, Vit C

-  Ketones

-  Detects acetoacetic acid only

-   NOT acetone or beta-hydroxybutric acid

-  +: Pregnancy, starvation, card free diets, ketoacidosis (DKA)

-  False +ve: highly pigmented urine, Levodopa

-  False –ve: delayed testing of urine sample

-  Bilirubin & Urobilinogen

-  +: bilirubinuria, hyperbilirubinaemia, elevated urinary nitrites (UTI)

-  Nitrites

-  +: UTI

-   Not produced by all UTIs, esp if young or neutropaenic

-   Sensitivity 45-60%

-   Specificity 85-98%

-  False +ve: air exposure

-  False –ve: rapid urine transit, decreased urinary nitrates, pH <6.0, urobilinogenuria, Vit C

-  Leucocyte Esterase

-  +: pyuria (UTI..)

-   Sensitivity 48-86%

-   Specificity 17-93%

-  False +: vaginal contamination or foreskin, other febrile illnesses (URTI, pneumonia..)

 

 

 

References

 

www.patient.co.uk/doctor/Urine-Dipstick-Analysis.htm

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