Transcript Tests
Tests Urinalysis, swabs and smears Urinalysis pH 7.4 – 6 Acidified in the distal tubules Difficult to interpret Specific Gravity Ability of body to concentrate urine Usually greater than 1.022 if not drunk for >12 hours If very raised > 1.035, contaminated/diabetes/radio opaque dyes. Protein Contamination with cells leads to erroneous protein levels Dipsticks use Bromophenol blue which is sensitive to albumin not other proteins i.e. globulins and Bence Jones proteins. Trace may be normal, + corresponds to 200 – 500 mg / 24 hours and so on. Micro albumin Not detected by standard dipstick. Usually expressed as an albumin/creatinine ratio. Urine collected in the morning. Screening for early diabetic nephropathy. Glucose Specific for glucose – not galactose or fructose( do not use in newborn for screening). If raised usually means diabetes mellitus. Remember possibility of low renal threshold. Ketones Diabetes or calorie deprivation. Nitrites Positive result indicates that bacteria may be present in significant numbers. Leucocytes Indicates the presence of white blood cells. If negative infection unlikely. Microscopic urinalysis 10 – 15 mls, centrifuged for 5 minutes. Decant – leave 0.2 ml. LPF and HPF. Red Blood Cells Beware of contamination – menstruation , catheterisation. In theory no rbc should be seen. If rbc dysmorphic – consider glomerular disease White blood cells Contamination – vagina and external urethra ( men and women). If > 2 wbc per HPF suggests infection. Epithelial cells From the renal tubules – some present normally , raised in conditions affecting the tubules or in neoplasia. Casts Mucoprotein secreted by the distal convoluted tubule. Low flow rate, high salt concentration and low ph make casts more likely. Can indicate glomerular disease or tubular damage Bacteria Contamination common >100,000/ml for significance Mixed growth suggests contamination Catheter and suprapubic specimen any organism is significant Yeast Usually contaminant Immunocompromised patient Crystals Normal – calcium oxalate, triple phosphate and amorphous phosphates. Others Sperm!! Ova ( schistosomiasis) Urine collection Random – prone to contamination Early morning – hypertonic and concentrated . Use for pregnosticon and microalbumin Clean catch, MSSU. Swabs Vaginal discharge. HVS – from the top of the vagina Candida and Bacterial vaginosis Cervical and other swabs Normal swab – looking for gonorrhea. Endocervical swab – ELISA looking for chlamydia Urethral swab if STD suspected Viral swab if herpes suspected Early morning urine for Chlamydia screening Smears Liquid based cytology Reduce number of inadequate to 1%. Where to take the smear from? Redcue false negatives Screening intervals 25 – 49 3 yearly 50 – 64 5 yearly 65+ no need if previously routinely screened and ok!! Results Inadequate Normal ( 94%) Metaplasia – no action Endocervical cells – no action Atrophic smear – no action ? oestrogen Result continued Endometrial cells – with IUCD , occ. in 1st half of cycle – may need further investigation Inflammatory changes – swabs Actinomyces – seen with IUCD. No clear what to do . If no symptoms leave alone , if symptomatic ? Change iucd Results continued Borderline +/- HPV – 6 months Mild dyskaryosis(4%) - CIN 1 – 6m Moderate dyskaryosis (<1%) – CIN2 – colposcopy Severe dyskaryosis – CIN3 – colposcopy 2-4%