Year 1 MBChB Clinical Skills Session Urinalysis

Transcription

1 Year 1 MBChB Clinical Skills Session Urinalysis Reviewed & ratified by: Dr V Taylor-Jones & Ms C Tierney.

2 Urinalysis Aims and Objectives Aim: For the student to be able to safely conduct a urinalysis on a sample of urine. Objective: The student will know the indications for urinalysis. Objective: The student will know how to obtain urine samples and perform urinalysis. Objective: The student will know how to document the urinalysis result. Theory and background Urinalysis can be used as a screening test to aid detection of abnormalities and aid diagnosis, also for monitoring and management of a patient s condition. This may be performed routinely as part of health check, well woman / well man clinic or if indicated by patient history and presentation. Urine Dipstick Analysis There are a large range of strips available, some are very specific eg. screen for glycosuria (the excretion of glucose in the urine.. Many have multiple tests on each strip, please check the test strips selected have the specific tests on that you require. Check that the container has not been left open and that the strips are in date. Ensure that you are clear about the timings required for each test and that you know how to read the strip accurately. You must be familiar with the strips that you are using. 2

3 What can you test for: Glucose is not normally present in the urine. Presence may be due to elevated blood glucose levels or reduced renal threshold. Protein (Albumin) albumin and globulin is normally in too low a concentration to give a positive reaction. False positive results occur in strongly alkaline urine. Abnormal proteinuria (the presence of an excess of serum proteins in the urine. is usually due to glomerular disease, which may be caused by a variety of conditions, including diabetes mellitus and hypertension. Blood suggests urological disease and/or urinary tract infection (UTI.. Results may be false positive if the container is contaminated with bleach, perianal skin, povidone iodine, stale urine or menstruation. ph Value is usually slightly acidic within ph 5-6 (range 4.8 to Lowest after overnight fast, highest after meals. Can be helpful when screening for renal disease, respiratory disease, certain metabolic disorders and specific therapeutic regimens, such as sodium bicarbonate. Nitrites are not normally present; produced by gram negative bacteria converting nitrates to nitrites. Ideally specimen should be obtained about 4 hours after last passing urine (voiding.. Indicates a UTI and the sample should be sent for further testing. Ketones are abnormal urinary constituents, being breakdown products of fatty acid metabolism. Bilirubin indicates hepatic or biliary disease. Urobilinogen is normally present in urine, elevated levels may indicate liver abnormalities or excessive destruction of red blood cells. Urobilinogen tests should be considered with the bilirubin result to provide a differential diagnosis. A false negative result may be obtained from a stale sample. 3

4 Leucocytes a positive result suggests pyuria (pus in the urine. associated with a UTI. Isolated results may not be significant. Repeated positives should not be ignored but be aware of possible sources of contamination or other factors which may limit sensitivity to this test. Specific Gravity (SG) sometimes called density. It is a laboratory test that measures the concentration of all chemical particles in the urine. Normal ranges given do vary between so do check your product instructions carefully. Increased SG is seen in conditions causing dehydration, glycosuria, renal failure, heart failure or inappropriate antidiuretic hormone secretion or proteinuria. Decreased SG may be seen in excessive fluid intake or renal failure or pyelonephritis. Tests can be falsely positive or falsely negative so remember to be aware of other factors Consider whether The sample could have been contaminated? The patient s medication could have affected the results or the sensitivity of the test? The patient s condition could have affected the results or sensitivity of the test? Urine Collection Listed below are a few examples of different collection types; Routine sample of urine MSSU mid stream sample of urine (most common collection method) First Pass Urine first few drops of urine, eg; in Chlamydia screening CSU catheter specimen of urine EMU early morning urine 24 hour urine 4

5 Some methods of collection; Paediatrics Urine bag Catheterised patients- Needle free collection port Images above supplied and permission granted by B. Braun Medical Ltd There are also many further types of devices that can be fitted to urine bottles to aid collection or urine can be collected in a sterile pot before transfer to a specimen bottle There are various ways of collecting urine find out what is recommended by your Trust. If the sample is to go for laboratory analysis/ culture then the process should be aseptic. 5

6 Specimen bottles may contain boric acid, please gently agitate bottle to mix contents MSU is the recommended routine collection method. Periurethral cleaning is only recommended if the sample is to go for analysis (water is considered sufficient.. The first part of voided urine is discarded and, without interrupting the flow, approximately 10mL is collected into a CE marked leak proof container, or a sterile pot and transferred to a sample bottle. The remaining urine is discarded. (Standards unit, PHE June 2017, pg 24. National guidance on this is below; 6/B_41i8.2.pdf Patient Safety 6

7 Procedure Consider the tests that are required and ensure that you know how to read the strip Prepare your equipment before you begin You should be bare below the elbows, and hair off your collar. You must put on a pair of gloves and a plastic apron prior to opening the sample container and wash your hands when you finish. 7

8 Take a moment to consider the colour and turbidity (cloudiness of the urine. as these may be significant - and be linked to pathology or dietary and drug causes. There are many variations in practice, you may write the results on a scrap piece of paper to transfer to the patient notes in a clean environment. Some clinical placements will have a machine that will analyse the dipstick and print the results, please check procedures in your working environment. Open the test strip container and remove a strip. Replace the top immediately Exposed strips absorb atmospheric moisture and renders the test zones inaccurate. Do not contaminate the strips by placing them on a table, use a clean surface or clean blue roll. 8

9 Briefly (no longer than one second) dip the test strip into the urine to wet all the test zones. There may be a control zone at the bottom of the strip- this should not be dipped Withdraw strip, dragging the edge along the rim of the container to remove excess fluid. Use the second hand of a watch to time the period since dipping. Take care as different tests require different times. 9

10 Place the strip on a piece of clean blue roll. Compare test zones with the colour scale on the side of the strip container at the time indicated by the manufacturer. The colours are stable for at least another minute allowing plenty of time for reading. NOTE your results. Documenting Results There are different methods for documenting the results, as mentioned previously; 1. After dipping the urine compare the strip with the scale and remember the results 2. Prepare your documentation sheet with as much information as possible, prior to dipping the strip. After dipping it, remove the glove from your dominant hand and document the results. 3. You may write the results on a scrap piece of paper to transfer to the patient notes (electronic or paper. in a clean environment. 10

11 Documenting Results The University of Liverpool Clinical Skills Teaching and Learning Centre Please report abnormal results immediately to a senior member of staff, and document clearly. Some Do s and Don ts Some Do s of urinalysis.do Check expiry date on container before use Replace cap & store strips in a cool, dry place Read instruction on pack insert Time accurately for each test on the strip 11

12 Dispose of ALL waste appropriately AND WASH YOUR HANDS AGAIN Document in full in black pen - including negative findings Report abnormal results IF it isn t recorded IT wasn t DONE And some Don ts of urinalysis DO NOT - Transfer strips to another pack DO NOT - Prolong dipping of test strip (1 second is enough. DO NOT - Hold the stick vertically after dipping DO NOT - Touch the test zone with fingers DO NOT Contaminate your pen or the patient notes with urine. References and other Useful Resources Sources and useful resources Public Health England 126/B_41i8.2.pdf Siemens Multistix 8 SG B.Braun at Urine Analysis App Siemens U.A app Urine Dipstick Analysis Patient PLUS article 12

13 Underlying anatomy and Physiology Peer Feedback 05 Y1 Urinalysis peer feedback.docx Video Glossary 13