Urine Collection and Processing

Collection and transport of urine

Each time possible, the primary urine passed with the aid of the affected person at the start of the day ought to be sent for examination. This specimen is the most focused and therefore the most appropriate for lifestyle, microscopy, and biochemical evaluation. Midstream urine (MSU) for microbiological examination is accrued as follows:

In a hospital with a microbiology laboratory

1 .Give the patient a sterile, dry, wide-necked, leak proof container and request a ten–20 ml specimen. Important: explain to the affected person the need to collect the urine with as little contamination as possible, i.e. a ‘smooth-catch’ specimen.

Female patients: Wash the hands. Cleanse the vicinity around the urethral commencing with clean water, dry the area with a sterile gauze pad, and collect the urine with the labia held apart.

Male patients: Wash the fingers before accumulating a specimen (center of the urine float). Be aware: whilst an affected person is in renal failure or a younger child, it could not be feasible to achieve various millilitres of urine.

2 Label the specimen with the date, the name and wide variety of the affected person, and the time of collection. As soon as possible, deliver the specimen with a request form to the laboratory. while instantaneous delivery to the laboratory isn't always viable, refrigerate the urine at four–6 °C. whilst a postpone in the transport of more than 2 hours is expected, upload boric acid preservative to the urine . Specimens containing boric acid want no longer be refrigerated.

In a health centre without a microbiology laboratory

1 .Provide the patient a sterile, dry, leak-proof field with instructions on how to acquire a clean-capture MSU.

2.Add a measured quantity of boric acid powder (0.1 g/10 ml of urine) to hold the specimen, and blend properly.

Note : A simple way of measuring mechanically the boric acid is to use a small slender tube (precipitin tube), marked to hold 0.2 g of the chemical (sufficient for 20 ml urine). This ‘measuring-tube’ can be kept connected to the neck of the boric acid container by an elastic band.

Important: Urine for culture need to no longer be preserved with a bactericidal chemical inclusive of thymol, bleach, hydrochloric acid, acetic acid, or chloroform. 3 Label the box, and send the urine with a requested shape to attain the Microbiology Laboratory inside 48 hours. whilst feasible observe the urine microscopically in the health Centre for bacteria and pus cells to display for urinary contamination.

Collection of urine while renal tuberculosis is suspected

The specimen will need to be tested in a Tuberculosis Reference Laboratory. The testing laboratory has to offer written instructions on the gathering of urine for the isolation of M. tuberculosis

Lab examination of urine

Day 1

1 Describe the advent of the specimen and record:

• the coloration of a specimen
• whether or not it's miles clear or cloudy (turbid)

Note: Other changes in the coloration of urine can be caused by the ingestion of positive ingredients, herbs, and tablets specifically vitamins everyday freshly surpassed urine is obvious and pale yellow to yellow depending on attention (see additionally urine biochemical exams.

Be aware: when left to face, a cloudiness might also expand because of the precipitation of urates in an acid urine or phosphates and carbonates in an alkaline urine. Urates may additionally provide the urine a pink-orange shade.

Observe the specimens microscopically

Urine is examined microscopically as a wet coaching to stumble on:

• good sized pyuria, i.e. WBCs in extra of 10 cells/_l (106/1) of urine
• purple cells
• casts
• yeast cells
• T. vaginalis motile trophozoites
• S. haematobium eggs
• Bacteria (supplying the urine is freshly accrued)

To diagnose urinary schistosomiasis microscopically, and to discover casts while few in variety, examination of a sediment from centrifuged urine is needed to pay attention the eggs and casts. Because concentration techniques aren't without difficulty standardized it's far hard to estimate white cellular numbers to set up whether or not there is enormous pyuria (pus cell numbers above normal). In practice, most district laboratories document the numbers of white cells in centrifuged urine as few, moderate range, or with only slight numbers and plenty of being seemed as enormous while investigating UTI. Exam of a Gram-stained smear offers extra useful facts .

Preparation

1 .Aseptically switch about 10 ml of well-mixed urine to a labelled conical tube.

2.Centrifuge at 500–a thousand g for 5 minutes. Pour the supernatant fluid (by way of completely inverting the tube) into a second container no longer the unique one. this can be used for biochemical exams to keep away from contaminating the authentic urine which can also want to be cultured (relying on the findings of the microscopical examination).

3.Remix the sediment by tapping the bottom of the tube. Transfer one drop of the properly-mixed sediment to a slide and cover with cover glass. Be aware: Do now not discard the ultimate sediment because this may be had to put together a Gram smear if WBCs and, or, bacteria are visible inside the moist training.

4.Have a look at the preparation microscopically the use of the 10_ and 40_ objective with the condenser iris closed sufficiently to give exact contrast. File the subsequent: microorganism (document handiest whilst the urine is freshly surpassed): generally seen as rods, but sometimes cocci or streptococci . Bacteriuria is usually followed by pyuria (pus cells in urine).

White cells (pus cells): those are round, 10–15 _m in diameter, cells that contain granules . In urinary infections, they are frequently located in clumps. In urine sediments, white blood cells (WBC) are normally pronounced as: Few: Up to 10 WBCs/HPF (excessive strength field, i.e. the use of 40_ objective) moderate number: eleven–40/HPF Many: extra than 40 WBC/HPF

Red cells: Those are smaller and more refractile than white cells . They have a precise define and contain no granules. While the urine is isotonic, They have a ringed look . They are usually mentioned as few, mild or many in the range consistent with excessive strength discipline .Haematuria (purple cells in urine) can be found in urinary schistosomiasis (normally with proteinuria), bacterial infections, acute glomerulonephritis (irritation of the glomeruli of the kidneys), sickle mobile disorder, leptospirosis, infective endocarditis, calculi (stones) within the urinary tract, malignancy of the urinary tract, and haemorrhagic conditions.

Note: The finding of crimson cells in the urine of ladies can be due to menstruation.

Casts: Those can commonly be seen with the 10_ objective supplied the condenser iris is closed sufficiently to offer proper contrast. They encompass solidified protein and are cylindrical in shape due to the fact they may be formed in the kidney tubules. the subsequent casts may be found in urine:

• Halyne casts, which might be colourless and empty (see Plate 7.12). they are related to damage to the glomerular filter membrane. A few can be visible following strenuous exercising or for the duration of fever.

• Waxy casts, which are hyaline casts which have remained within the kidney tubules a long time. they are thicker and denser than hyaline casts, often appear indented or twisted, and may be yellow in coloration They usually suggest tubular damage and might sometimes be visible in renal failure.

• Cell casts, which incorporate white cells or red cell. Purple cellular casts appear orange-red.They imply haemorrhage into the renal tubules or glomerular bleeding. White cell casts are observed while there's infection of the kidney pelvis or tubules. Yellow-brown pigmented casts may be visible inside the urine of jaundiced sufferers.

• Granular casts, which include irregular sized granules originating from degenerate cells and protein. They're additionally related to renal harm.

Epithelial cells:

These are without problems seen with the 10_ objective . They are nucleated and vary in size and form. They may be usually said as few, moderate, or many in the range consistent with low strength (10_ objective) discipline. It's far regular to find a few epithelial cells in urine. when visible in big numbers.However, they typically indicate the infection of the urinary tract or vaginal infection of the specimen.

Yeast cells:

Those can be differentiated from purple cells via their oval shape and some of the yeasts normally display single budding. If in doubt, run a drop of dilute acetic acid under the duvet glass. Purple cells can be haemolyzed by the acid, but not yeast cells. Yeast cells are normally stated as few, moderate, or much consistent with HPF. They may be seen within the urine of women with vaginal candidiasis, and now and again in specimens from diabetics and people with immunosuppression.

Trichomonas vaginalis:

Discovered in the urine of ladies with acute vaginitis (sometimes visible in the urine of fellows). The trichomonads are a little larger than white cells and are generally easily detected in sparkling urine due to the fact they're motile. They move by flagella and an undulating membrane .

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Eggs of S. haematobium:

Identified by using their big length (about a hundred forty-five _ 55 _m) and backbone at one give up . and shade Plate . The urine will contain red cells and protein.

Those have a function refractile look. Ordinary urine incorporates many chemicals from which crystals can form, and consequently the locating of most crystals has little importance. Crystals need to be looked for in fresh urine whilst calculi (stones) in the urinary tract are suspected. Crystals which may be located in uncommon issues include:

• Cystine crystals, which might be identified with the aid of their six-facets.They're soluble in 30% v/v hydrochloric acid (in contrast to uric acid crystals which they will resemble). They can be located in cystinuria, an unprecedented congenital metabolic sickness in which cystine is excreted in the urine.
• Cholesterol crystals, which look like rectangles with cut-out corners . They are insoluble in acids and alkalis, however, soluble in ether, ethanol, and chloroform. they're hardly ever discovered except in intense kidney disease or whilst a lymphatic vessel has ruptured into the renal pelvis.
• Tyrosine crystals, which can be yellow or dark coloured and seem like needles massed together . They may be insoluble in ethanol, ether, and acetone. they're occasionally discovered in severe liver ailment.

Spermatozoa:

Once in a while located inside the urine of guys, they may be effortlessly recognized by way of their head and lengthy thread-like tail. They will be motile in clean urine.

References:

D greenwood, Slack RCB and J Peutherer.Medical microbiology.2001.

JG College, AG Fraser and BP Marmion.Practical Medical microbiology.Fourteenth Edition. Churchill Livingstone, 1996.

JP Micheal, ECS Chan and NR Krieg.Microbiology.Fifth Edition. Delhi: Mcgraw-hill, 1993.

M Cheesbrugh.Medical laboratory manual for tropical countries.London, 2007.