15. Principles of elimination management
urinalysis
CHAPTER CONTENTS
The physical characteristics of urine120
Indications for urinalysis120
Role and responsibilities of the midwife122
Summary122
Self-assessment exercises122
References122
LEARNING OUTCOMES
Having read this chapter the reader should be able to:
• discuss the midwife’s role and responsibilities in relation to urinalysis, identifying when and how it is undertaken
• recognise ‘normal’ urine and gain some understanding of the significance of the findings of urinalysis.
This chapter considers ‘normal’ urine, changes that may occur during childbirth, the significance of abnormal findings and the procedure for undertaking urinalysis. Although pregnancy tests can also be undertaken using a specimen of urine, this is not discussed within this chapter. Whilst urinalysis is an effective screening tool, it should not be used in isolation when considering whether or not treatment is required (Steggall 2007).
Definition
Urinalysis is the testing of both the physical characteristics and the composition of freshly voided urine. It is undertaken for the purposes of:
• screening: for systemic and renal disease
• diagnosis: of a suspected condition
• management: to monitor the progress of a particular condition (Getliffe & Dolman 1997), e.g. pregnancy-induced hypertension.
Urinalysis can be undertaken by laboratory testing or, for immediate results, by using a chemical reagent strip, in addition to assessing the physical characteristics of colour, clarity and odour of urine.
The physical characteristics of urine
• Clarity: urine is usually transparent when freshly voided.
• Odour: urine has a characteristic inoffensive odour.
Composition of urine
Urine has a pH of 4.5–8, specific gravity of 1.003–1.030 and is mainly water (96%) with 4% dissolved substances:
• urea (2%)
• uric acid, creatinine, sodium, potassium, phosphates, sulphates, oxalates and chlorides
• cellular components, e.g. epithelial cells, leucocytes
• protein and glucose are present in negligible amounts, normally undetectable by routine testing.
Normal changes during childbirth
• Pregnancy: glycosuria is more common due to changes in renal function (Blackburn 2007).
• Labour: proteinuria may occur following rupture of the membranes or as a result of contamination by the vaginal discharge or the operculum.
• Ketonuria: may occur and, provided it is mild, is insignificant.
Indications for urinalysis
• As part of the antenatal examination.
• Throughout labour.
• On admission to hospital for any reason as a baseline observation.
• Specific maternal disorders or treatment, e.g. hypertensive disease, diabetes mellitus, anticoagulant therapy.
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