¾ Many drugs are also responsible for urinary color change • Cascara and senna laxatives in acidic urine will turn the urine reddish-brown, in alkaline urine they will turn the urine red • Phenazopyridine (pyridium), amido pyrine turn

 

defined by the sum of the number of protons and neutrons

in its nucleus. Elements have more than one isotope with

varying numbers of neutrons. For example, there are two

common isotopes of carbon, 12C and 13C which have 6

and 7 neutrons respectively. The abundances of different

isotopes of elements vary in nature depending on the source

of materials. For relative abundances of isotopes in nature

see reference on Isotopic Composition of the Elements.

Atomic Weight

Atomic weight values represent weighted average of

the masses of all naturally occurring isotopes of an

element. The values shown here are based on the IUPAC

Commission determinations (Pure Appl. Chem. 73:667-

83, 2001). The elements marked with an asterisk have

no stable nuclides. For these elements, the weight value

shown represents the mass number of the longest-lived

isotope of the element.

Electron Configuration

The distribution of electrons according to the energy

sublevels (subshells) in uncharged atoms. The noble gas

shown in square brackets (e.g. [He]), marks that all the

subshells associated with that element are fully occupied

by electrons.

Fundamental Chemistry 55

PERIODIC TABLE OF THE ELEMENTS

Urine Analysis

C H A P T E R 5

COMPOSITION OF URINE

Urine composition is affected mainly by three factors:

1. Nutritional status

2. State of metabolic processes

3. Ability of the kidney to selectively handle the material

presented to it.

Physiochemical Characteristics of Urine

Dry weight 55–70 g/24 h

Osmolality 38–1400 mOsm/kg water

 (Average = 500–800

 mOsm/kg water)

pH 4.6–8.0 (mean = 6.1)

Specific gravity

Neonates 1.012

Infants 1.002–1.006

Adults 1.003–1.030

Volume Per day

Neonates: 30–60 mL

10–60 days 250–450 mL

60–365 days 400–500 mL

Children:

1–3 years 500–600 mL

3–5 years 600–700 mL

5–8 years 650–1000 mL

8–14 years 800–1400 mL

Adults: 600–2500 mL

 (Avg: 1200 mL)

Inorganic Constituents per 24 Hours

Iron 0.06–0.1 mg

Chlorides 6 (4–10) g on usual diet

Sodium 4 g on usual diet

Phosphate 0.8–1.3 g on usual diet

Sulfur 2 g

Calcium < 150 mg.

Organic Constituents per 24 Hours

Nitrogenous—total 25–35 g

Urea 15–30 g

Creatinine 1.4 (1–1.8) g

Ammonia 0.7 (0.3–1) g

Uric acid 0.45 (0.3–0.6) g

Protein (albumin) 0–0.1 g

Creatine, in children 10–50 mg (excreted in urine

in adults in hepatic or muscle

disorders or thyrotoxicosis)

Glucose (fasting range) 2–20 mg%

 (Diabetic may lose up to

 100 g/day)

Amylase (diastase) 40–260 units/hour.

Cells and Casts (Table 5.1)

TABLE 5.1: As per Addis count

Range Mean

RBC Up to 1 million /day

(more in females)

130,000/day

Casts

hyaline and

occasionally

granular

Up to 5,000/day 2,000/day

Leukocytes Up to 5 million/hour

(more in females)

108,000/h, females;

28,000/ h, males

Epithelial cells Up to 2.5 lakh/hour

(more in males)

68,000/h, females;

78,000/h. males.

Squamous cells

epithelial

Variable

Urine Analysis 57

Collection of Urine

The urine sample should be collected in a clean, dry

container and should be examined fresh. For cultures,

sterile containers should be used. With time, RBC, and

leucocytes tend to be destroyed due to hypotonicity of

the urine. Casts too tend to get decomposed. Bacterial

contamination of stale urine is frequent and causes

alkalinization of the urine due to conversion of urea to

ammonia and loss of glucose. This rise in pH accelerates

loss of leucocytes and epithelial cells. For ordinary

qualitative, tests a random sample is enough. For diabetes

mellitus, a 2-hour postprandial sample is desirable; for

nephritis, a morning specimen is best as it has higher

specific gravity and lower pH desirable for preservation of

formed elements.

Repeated samples are necessary sometimes, as for

orthostatic proteinuria.

Whenever needed, a 24-hour urine should be collected

in a large container. Have patient void and discard urine

at any particular time, save all urine for the next 24 hours,

and then void at the same hour to finish the collection.

Preservation of Specimen

Urinary decomposition occurs quickly in warm temperatures. Hence, fresh specimens should be examined,

if not, then it should be refrigerated. As far as possible,

the need for preservation should not arise. However, the

following preservatives can be used:

1. Toluol Best for preservation of chemical constituents. Add 2 mL toluol/100 mL urine.

2. Thymol A small floating lump of thymol can

preserve the urine for several days in a

bottle. Thymol may, however, cause a

false-positive reaction for protein.

3. Formalin 1 drop/30 mL urine. Is good for preserving

formed elements. It can precipitate

proteins and can reduce Benedict’s

solution.

4. Boric acid 0.3 g/120 mL of urine. However, yeasts

can still grow and uric acid crystals get

precipitated.

GROSS EXAMINATION OF URINE

Color and Appearance

Normal urine is clear and pale yellow (straw) in color.

1. Colorless: Dilution; diabetes mellitus/insipidus,

nervousness, diuretic or alcohol intake.

2. Milky: Purulent genitourinary tract disease; chyluria.

3. Orange: Urobilinogenuria, fever, excessive sweating,

concentrated urine.

4. Red: Beetroot ingestion, hematuria, hemoglobinuria,

phenolphthalein, pyridinium sulfo♥nate.

5. Greenish: Jaundice, phenol poisoning.

6. Dirty blue or green: Putrefying urine, in typhus or

cholera, methylene blue.

7. Dark brown, brown red, or yellow: Very concentrated

urine, acute febrile diseases, bilirubinuria.

8. Brown-yellow or brown red (if acidic) or bright red (if

alkaline): Due to rhubarb, cascara, aloes.

9. Brown, brown black or black: Hemorrhage in urinary

tract if urine is acidic (Acid-hematin); hemoglobinuria;

porphyria, methemoglobinuria; myoglobinuria,

melanin, phenol poisoning, homogentisic acid (alkaptonuria). In porphyria, urine turns dark brown on

exposure to sunlight or boiling.

Interfering Factors

¾ Normally, urine darkens on standing. This occurs

because of oxidation of urobilinogen to urobilin.

Decomposition of urine commences in half an hour.

¾ Some foods cause change in urine color

• Beets turn the urine red

• Rhubarb changes color of urine to brown.

¾ Many drugs are also responsible for urinary color change

• Cascara and senna laxatives in acidic urine will turn

the urine reddish-brown, in alkaline urine they will

turn the urine red

• Phenazopyridine (pyridium), amido pyrine turn

urine orange in color

• Pyridium, ethoxazene turn urine to orange/orange red

• Orange to purple red may occur due to chlorzoxazone

• Salicylazosulfapyridine, anisindone, or phenindione

turn urine color to orange-yellow in alkaline urine

• Sulfonamides and nitrofurantoins produce rustyellow to brownish color

• Dilantin (diphenylhydantoin) dioctyl calcium

sulfosuccinate, phenolphthalein and phenothiazine

turn urine color to pink to red or red-brown

• Phenolphthalein may also produce magenta color

• Amidopyrine, pyridium, aniline dyes, BSP, PSP in