Intro to Urinalysis

What are the basic observations used to give diagnostic information?

color, turbidity, odor, volume, viscosity, sweetness)

Uroscopy

the visual examination of urine

What are pre-examination variables?

specimen collection, handling, storage

Examination variables:

reagent and test performance, instrument, personnel and competency

Post-examination variables:

reporting of results and interpretation

3 qualities a urinalysis procedure manual must be/have:

- contain all procedures performed in this section of the lab
-comply w/ CLSI guidelines
-any changes must be taught/reviewed by performing staff

QA

overall process of guaranteeing quality in pt care and regulates throughout the whole system

What needs to bee on the requisition form?

-date/time of collection and recieved
-refrigeration
-tests requested
-special instructions
-patient identifiers

Why would a doctor order testing on a urine sample (advantages)?

-readily available and easy to collect
-contains diagnostic info (metabolic function)

Current methods of urine testing

-physical
-chemical
-microscopic
-confirmatory

Urine formation:

continuously formed by the kidneys as an ultra filtrate of plasma

What is the normal urine output and how much plasma is filtered daily?

urine output: 1200 to 1500 mL/day
plasma filtered: 170,000 mL

Urine composition:

-depends on diet, activity, metabolism
-95% water + 5% solutes

What solutes can be found in urine?

urea, creatinine, uric acid, and inorganic Cl and Na (also hormones, vitamins, and meds)

What would you check in a suspicious urine sample?

urea and creatinine

Oliguria

decreased urine output (dehydration)

Anuria

cessation of urine flow (possible damage to kidneys)

Nocturia

increased urination at night

polyuria

increased urine output (diabetes and diuretics)

Polydipsia

increased ingestion of water

Diabetes Mellitus

-dec insulin production
-HIGH specific gravity, increased glucose

Diabetes Insipidus

-dec in ADH
-LOW specific gravity

What factors can be considered when testing sample integrity?

-within 2 hours of collection
-increased bacteria, nitrite, odor, or pH
-decreased cells, casts, glucose, ketones, bilirubin, urobilinogen

What is the ideal temperature to store urine specimens?

2-8 degrees C (must return to room temp before testing)

Specimen rejection criteria

-unlabeled container
-label/requisition don't match
-contamination w/ feces or tp
-containers are contaminated on the outside
-QNS
-improper transport/handling

What is the ideal preservative for urine samples?

bactericidal (inhibits urease and preserves formed elements in the sediment)

purpose of Random specimen

routine testing

purpose of First morning (concentrated urine)

routine testing, pregnancy tests, and orthostatic protein

Purpose of 24 hour urine

quantitative chemical tests

Purpose of catheterized specimen

bacterial culture, or Drugs of Abuse on adolescents who are unwilling or unconscious)

Midstream clean-catch purpose

routine testing or bacterial cultures

Purpose of suprapubic aspiration

bladder urine for bacterial cultures, cytology

purpose of three and four glass collection

prostatic infection

Chain of custody

documentation from the time of specimen collection until the time of receipt of lab results

Points to consider when collecting a drug specimen

-photo ID of urine donor
-no unauthorized access to specimen
-no adulteration, subs, or dilution of specimen
-chain of custody

Witnessed vs. unwitnessed collection

-witness must be the same gender
-determined by test ordered
-both specimens must be handed immediately to collector

Adulteration tests

- temp taken within 4 minutes
- must be 32.5 - 37.7 C
- report temperatures outside range
- inspect urine color for anything unusual