The cytoplasm of a lymphocyte is clear sky blue, scanty, with few unevenly distributed, azurophilic granules with a halo around them. The nucleus is generally round or oval or slightly indented, and the chromatin is lumpy and condensed at the periphery.
The largest of the normal white blood cells is the monocyte. Its color resembles that of a lymphocyte, but its cytoplasm is a muddy gray-blue. The nucleus is lobulated, deeply indented or horseshoe-shaped, and has a relatively fine chromatin structure. Occasionally the cytoplasm is more abundant than in the lymphocyte.
The cytoplasm of a neutrophil has numerous fine lilac-colored granules, which sometimes are hardly visible. The nucleus is dark purple or reddish purple, and it maybe oval, horseshoe-or S-shaped, or segmented (lobulated). The neutrophil is further subclassified according to age as:
a. Metamyelocyte (also called juvenile). This is the youngest neutrophil generally reported. The nucleus is fat, indented, and is usually bean shaped or cashew nut shaped.
b. Band (sometimes called stab). This is the older or intermediate neutrophil. The nucleus has started to elongate and has curved itself into a horseshoe-or S-shape. As the band ages, it progresses to:
c. Segmented. The nucleus is separated into two, three, four, or five segments or lobes.
d. Hypersegmented. The nucleus is divided into six or more segments or lobes.
The physical and chemical properties of normal urine are markedly constant; any abnormalities are easily detected. The use of simple tests provides the physician with helpful information concerning the diagnosis and management of many diseases.
This section will deal with the routine and microscopic examination of urine specimens, some of the principles involved, and some of the simpler interpretations of the findings.
Urine specimens for routine examinations must be collected in aseptically clean containers. Unless circumstances warrant, catheterization should be avoided because it may cause urinary tract infections. Specimens of female patients are likely to be contaminated with albumin and blood from menstrual discharge, or with albumin and pus from vaginal discharge. For bacteriologic studies, care must be taken to ensure that the external genitalia have been thoroughly cleansed with soap and water. The patient must then void the initial stream of urine into the toilet or a suitable container and the remainder directly into a sterile container. All urine specimens should be examined when freshly voided or should be refrigerated to prevent decomposition of urinary constituents and to limit bacterial growth.
This is a sample of urine voided without regard to the time of day or fasting state. This sample is satisfactory for most routine urinalyses. It is the least valid specimen, since tests results may reflect a particular meal or fluid intake.
This is the first specimen of urine voided upon rising. It is the best sample for routine urinalysis because it is usually concentrated and more likely to reveal abnormalities. If positive results are obtained from the first morning specimen, the physician may order a 24-hour specimen for quantitative studies.
This specimen measures the exact output of a specific substance over a 24-hour period. To collect this specimen:
1. Have the patient empty his or her bladder at 0800. Discard this urine.
2. Collect all urine voided during the next 24 hours.
3. At 0800 the following day (end of 24-hour period), instruct the patient to empty his or her bladder.. Add this urine to the pooled specimen.
4. Specimen must be refrigerated during collection.
5. Preservatives will be added to the first specimen voided, according to the types of tests being ordered.