The Tests for Albumins doles

CHAPTER II. The Tests for Albumins doles

CHapTER III.

The Tests for Sugar, Acetone, Acetoacetic Acid, and Oxybutyric

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CHAPTER IV. ‘The Coloring-matters in Urine. Biliary Acids -

Cuaprer V. Determination of Uric Acid. Hippuric Acid -

CuapTer VI. Urea a

CHAPTER VII. The Determination of Phosphates, Chlorides, and Sulphates

CHAPTER VIII. Ammonia, Xanthin and Allied Bodies, and Creatinin - -

CHAPTER IX. The Sediment from Urine... .--.--

CHAPTER X. Unorganized Sediments and Calculi

APPENDIX. Tables and Notes pee ee

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105

119

145

167

“175,

223

URINE ANALYSIS

CHAPTER | OUTLINE OF TESTS. PRELIMINARY TESTS

The importance of an accurate knowledge of the bodies excreted by the urine has long been recognized and elaborate investigations have been carried out to determine the nature and quantities of these substances, some of which appear normally in health, while others are found only during the progress of disease.

Experiment shows that normally certain products occur in the urine in relatively large amounts, and give to it its prominent characteristics, while of other products the amounts present are so minute that their detection is a matter of no little difficulty.

Certain grave disorders are accompanied by the appearance of certain substances in the urine, and where the chemical or microscopic tests for the latter are simple and unquestionably correct we have at hand aconvenient aid to diagnosis. In many cases, how- ever, it is true that we are unable to trace the relation between smnall amounts of substances occasionally ap- pearing in urine and any specific disorder or condition of the body. The detection of such substances is nat-

urally without value in diagnosis, at the present time. I

2 URINE ANALYSIS

Yet it would be unwise to neglect the study of such traces because, as medical science progresses, new rela- tions are from time to time brought to light which give value to data which at one time may have been considered wholly unimportant. Complete handbooks on the urine give prominence to many topics which will not be touched upon in what follows because we are here concerned with phenomena, everywhere rec- ognized as important and the bearings of which, in the main at least, are understood.

In the practical analysis of urine, such as is custom- ary for clinical purposes, comparatively few tests are required, and little apparatus is necessary beyond that already used for other examinations. Frequently a single test is sufficient to determine all the physician needs to know; for instance, regarding the presence or absence of sugar or albumin.

In the following pages those tests and processes will be described which have been shown by experi- ence to be amply sufficient for all practical require- ments. Some of these are qualitative, others quanti- tative, and may be tabulated as follows:

. Observation of color and odor.

. The reaction, whether acid or alkaline.

. The tests for albumin.

. The tests for sugar.

. The tests for the characteristic biliary acids and coloring-matters.

The various tests for blood.

. Tests for other coloring-matters.

. The examination of the sediment.

Qualitative tests. APoOnn

PWD

PRELIMINARY TESTS 3

g. Determination of specific gravity.

z 10. “ “* the amount of albumin.

e 1. “ oe “sugar.

D4 12. “ “ “ “uric acid.

3 13. “ “ “ “urea.

i 14. e woe ‘« phosphates. LIS: Ee a OS ‘chlorides.

The above includes the usual and important tests. A few others will be given in the proper place; for instance, tests for acetone and diacetic acid, which under circumstances may have importance.

Normally, urine contains as its most important constituents urea, sodium chloride, certain phosphates and urates, and smaller amounts of other substances as hippuric acid, xanthin, creatinin, traces of phenols, etc.

Several writers have given the results of complete urine analyses in tabular form. These results are not very concordant, as might be expected from the char- acter of urine itself. Two tables often quoted will be given here for comparison.

According to Thudichum the average volume of urine passed per day is 1400 to 1600 cc., and the solid matter contained in the daily excretion he gives as follows, for a man weighing about 140 pounds.

Grams. Urea - - - - - - 30-40 Uric acid - - - - - - 0.50 Creatin and creatinin - - - 0.75, Hippuric acid - - - - - 0.50 Cryptophanic acid - - - - 0.65 Biliary acids - - - - - 0.012

Acetic acid - - - - - 0.288

4 URINE ANALYSIS

Grams. Formic acid - - - - - > 0.05 Sulphuric acid, SO, - - - - 2.00 Other sulphur combinations - - > 0.20 Alkaline phosphates - - - - 3-66 Earthy phosphates - - - - 1.28 Lime - - : - - - 0.17 Magnesia - - - = 0.19 Potassium and sodium chlorides - - 11.50 Ammonia - - - - - - 0.70

Traces of other bodies are given by Thudichum, but in amounts too small for determination. "Another table given by Parkes presents a better arrangement, and is here given; the figures refer to the amounts excreted in twenty-four hours by a man weighing about 145 pounds.

Grams. Urea - - - - - - = 33-18 Uricacid - - = - ee 0.55 Hippuric acid - - - - - 0.40 Creatinin - - - 0.91 Organic acids and pigments, . - = 10,00 Sulphuric acid, SO, - - - 2.01 Phosphoric acid. P,O, - - - > 3.16 Calcium - - : - - 0.26 Magnesium - : - : : - 0.21 Potassium - - - - - - 2.50 Sodium - - - : - > 11.09 Chlorine - - - - - - 7-50 Ammonia - - : - - - 0.77

It is evident that the character of the urine depends very largely on the diet, and this is shown in a clear manner by the figures in the following table, which were obtained by Bunge by the analysis of the urine of a healthy man, fed first on a meat diet, and later

PRELIMINARY TESTS 5

on one of wheat bread with salt and butter. Water was freely drunk in both tests.

Meat diet. Bread diet.

ce. cc. Volume in twenty-four hours. 1672 1920 Grams. Grams,

Urea - - - - 67.2 20.6 Creatinin = - -=- 2.163 0.961 Uric acid - -ST- 1.398 0.253, Sulphuric acid, SO, - 4-674 1.265 Phosphoric acid, PO, = - = 3.437 1.658 Lime - - : - 0.328 Oo. 39 Magnesia - : > 0.294 0.139 Potash - : 3-308 1.314 Soda - - - + 3.991 3-923 Chlorine = - - - 3-817 4.996

These figures represent, of course, extreme cases, but their practical importance is readily recognized.

Pathologically there may appear albumin, sugar, blood, pus, bile pigments and acids, and a number of other bodies insoluble, or of slight solubility, which usually appear as a sediment.

We turn now to an explanation of the various pre- liminary tests employed.

Specific Gravity

The density or specific gravity of the urine secreted in twenty-four hours, varies in health between rather wide limits, probably between 1.005 and 1.030. Ct.020, No may be taken as about the mean value at 15° C. —- The specific gravity depends primarily on the amounts of liquid and solid food taken, and on the loss of water from the skin by perspiration. When

6 URINE ANALYSIS

this loss is great the specific gravity of the urine is correspondingly increased, other things being equal.

In disease the density may be lowered below or in- creased above the normal value.

Foran absolutely exact determination of the density the use of the pycnometer, Mohir- Westphal balance, or other ap- paratus is necessary, but for our purpose the urzzometer, or den- sity bulb, is sufficiently accu- rate. This little instrument is shown in the adjoining figure. The urine to be tested is poured into a narrow jar, about one cm. wider than the bulb, and after the air bubbles have escaped the urinometer is immersed in it. When it comes to rest the degree at which it stands is read off below the surface. Usu- ally the last two figures only of the density are marked on the stem, as 25, instead of 1.025, and these are often given as the density.

As the density of urine de- creases about one degree for an increase in temperature of 3° to 5°C. itis important that the test be made at a “definite known temperature, as 15° or 25° C. Urinometers have usually been graduated to

PRELIMINARY TESTS 7

give the correct reading at a temperature of 15.5° C. (60° F.). But at the present time we have them for the temperature of 25° C. (77° F.), because this is with us a more common house temperature than the lower one. It is convenient to have the instrument indi- cate the correct specific gravity without the necessity of cooling. The specific gravity of urine varies ap- proximately as does that of water, with changes of temperature. A table in the appendix shows the rate for water, and by the use of this a correction can be made.

By noting the amount of urine passed in twenty- four hours, and the density of the mixed liquid, a rough determination of the solid matters contained in it can be made. For this purpose it is simply necessary to multiply the last two figures of the density by 2.33 (known as the coefficient of Haeser), which gives the approximate number of grams in a liter. By propor- tion the amount for the day can be calculated from this.

For example, 1,400 ce. of urine was passed, and its density was found to be 1.024.

Then, 24 X 2.33 = 55.92, and, 1,000: 1,400 :: 55.92: + = 78.288,

This calculation is frequently of service.

As indicated above a variation in the specific gravity of normal urine may be due to several causes, the most_important of which are changes in the volume of water drunk or the weight of nitrogenous food and salt digested. The amount of urine excreted daily may be taken as 1,500 cc. in the mean. Assuming

8 URINE ANALYSIS

that 15 grams daily is the salt consumption and that it is all excreted with the urine we have through this factor alone a specific gravity of about 1.007. Assu- ming further that 150 grams of nitrogenous food (con- sidered as pure albumin) are consumed daily and that four-fifths of this amount is daily excreted as urea, the weight of the latter in the urine would be 43 grams. This alone would produce a density of nearly 1.008 and give a percentage composition of 2.84. Combined with the other substances in urine the relative effect of the addition of urea would be greater. All of the solids of the urine havea specific gravity greater than that of water and their presence therefore adds to the specific gravity of the excretion, but changes in the density, due to changes in the amounts of uric acid, phosphates, sulphates, etc., passed, are of less impor- tance because of the relatively small quantities of these substances normally present.

If, with the food consumed normal, the water taken | is small in amount, or if a large amount is lost from the skin as perspiration then the density of the excre- ted urine must be correspondingly higher. A large volume of water consumed or little evaporation from the skin will give a urine of lower density. It is plain, therefore, that great variations in the specific gravity of the urine may occur and from perfectly nor- mal causes.

In disease even greater variations may occur, one of the most characteristic and important being that due to the presence of sugar in diabetes mellitus. Here the density may reach 1.040 or higher, while the vol-

PRELIMINARY TESTS 9

ume of urine is above 1,500 or 2,000 cc. in the twen- ty-four hours. A high specific gravity with /arge vol- ume is always suspicious and suggests presence of dex> trose, although occasionally it may be due to presence of large doses of soluble salts taken into the system as remedial agents. A low specific gravity with smad/ volume of urine must also call for investigation, as this points to the absence of, or marked decrease in, the nor- mal constituents from some cause. A lower density is observed in diseases where the elimination of urea is slower because of hindered tissue changes, in con- ditions of malnutrition in general, and in any disease involving the structure of the liver itself. In acute yellow atrophy of the liver, for instance, urea is much diminished, and the specific gravity low.

The diminution in excreted chlorides, with normal consumption, in certain diseases is also a factor in causing low specific gravity. This may follow when the salt consumed is eliminated temporarily in various exudations or effusions rather than by the normal channel.

Some of these indications will receive attention later during the discussion of the tests for the common normal and abnormal urine constituents.

Reaction

In health the reaction of the mixed urine passed through twenty-four hours is always acid.

This normal acid reaction is supposed to be due to the presence of acid phosphates and to small amounts of uric acid and to other free organic acids. The

10 URINE ANALYSIS

reaction can be observed by the aid of sensitive litmus paper, but the absolute amount of free acid is very small.

Occasionally urine is passed which gives the so- called amphoteric reaction with litmus; that is, it turns blue paper red and red paper blue. It has not been found possible to connect this phenomenon with certainty with any definite pathological condition; it has, therefore, no special clinical significance at the present time. Some hours-after-e—hearty—meal an lalkaline reaction is frequently observed, giving place oon to the usual acid condition. This alkaline reac- tion may be due to the presence of small amounts of trisodium phosphate formed during active digestion. The administration of alkaline carbonates, or of certain organic salts, as malates, acetates, tartrates, or citrates, which yield carbonates by final decomposition, may also occasion an alkaline condition. It should be observed that the character of the food consumed has much to do with the quality of the urine as regards acidity or alkalinity. In the consumption of products rich in proteids the oxidation of the sulphur gives rise to sulphuric acid which converts the alkali phosphate of the blood into acid phosphate before excre- tion. With a diet low in proteids the acidity is greatly decreased. Sometime after it is voided urine always becomes strongly alkaline in reaction, but this change may be delayed for days or weeks even. It is brought about by the decomposition of urea, which is usually a result of bacterial action. In this decomposition ammonium carbonate is formed, the odor of which

PRELIMINARY TESTS Ir

often becomes very strong. Anything which prevents or impedes the bacterial activity tends to maintain the ordinary acid or neutral reaction. Salicylic acid, thymol, chloroform, volatile oils, and other antifer- ments behave in this manner, and are frequently added tospecimensof urine to preserve them for investigation. For the preservation of 100 cc. of urine one-fourth of a‘gram of salicylic acid is enough.

Sometimes the decomposition of the urea takes place in the bladder, the voided urine having then a very marked alkaline reaction and strong odor, usually. Such a change may be brought about by the progress of disease, or may be induced by the introduction of adirty catheter into the bladder. This carries the organ- ism capable of splitting up the urea, and the condition once established may be maintained for a long time.

Ammonium carbonate results from the reaction. This may be distinguished from the fixed alkalies (hydroxide or carbonate of sodium or potassium) by a very simple test. A piece of sensitive red litmus paper immersed in alkaline urine becomes blue. On drying the paper the color due to the non-volatile alkalies persists, while that of ammonium carbonate disappears. The test has some practical value as it is necessary to distinguish between the alkalinity of urea fermentation and that of an excess of fixed alkali occasionally present. For these tests only fresh sensi- tive paper can be safely used. The conversion of urea into ammonium carbonate is represented by this equa- tion:

CON,H, + 2H,O = (NH,),CO,.

12 URINE ANALYSIS

In highly colored urines it is not always easy to observe the reaction with litmus paper. In this case a method often used in the examination of blood to determine its alkalinity may be applied. This con- sists in immersing small disks of plaster of Paris in neutral litmus solution and then drying them. A few drops of urine are placed on a disk and allowed to remain some minutes. The urine is then washed off leaving a bluish or reddish spot indicating the reaction.

An accurate*determination of the acidity of urine can not be readily made, but approximately a value may be obtained by adding afew drops of phenol- phthalein to 100 cc. of urine, and then running in tenth-normal sodium hydroxide solution until a per- manent pink color is secured. At this stage the acid phosphates of the type H,NaPO, are converted into the alkali phosphates of the type HNa,PO,, and for each cubic centimeter of alkali used 12 milligrams of H,NaPO, may be calculated as present. But on account of the color of the urine itself the process is at best somewhat uncertain.

To approximately determine the alkalinity add to 100 cc. of urine a few drops of phenolphthalein, and then tenth-normal sulphuric or hydrochloric acid until the color disappears. If the alkalinity is due to sodium carbonate, for each cc. of the acid used, calcu- late 5.3 milligrams of Na,CO, as present. If due to Na,PO, each cc. of alkali used corresponds to 8.2 milligrams. All such tests should be made in a beaker with a wide bottom placed over white paper so

PRELIMINARY TESTS 13

as to disclose a change of color as clearly as possible. For the preparation of the standard acid and alkali solutions used in these tests see the appendix.

Odor

The odor of urine is not easily described, as in health it is sz generis and characteristic. Normal urine contains traces of complex aromatic bodies, the exact nature of which cannot in all cases be given. These substances are more abundant after a vegetable than after an animal diet, and are especially note- worthy in the urine of persons whose food contains such vegetables as cabbage, radishes, parsnips, aspara- gus, or the spices. It is well known that certain sub- stances given as remedies give rise to distinct odors in the urine. The administration of turpentine imparts to the urine an odor of violets.

As the odor so largely depends on the nature of the food it may be much modified even in health, and in disease may be characteristically changed. The am- moniacal odor of urea decomposition in the bladder has been referred to, and the peculiar szweetish odor of diabetic urine has long been noticed.

But it must be remembered that many strong odors may be developed in the urine soon after passage by the action of ferments other than the micrococcus urea which yields ammonium carbonate. In some cases these give rise to what may be called a putre- factive odor.

Color

The color of urine is described as straw-yellow.

14 URINE ANALYSIS

Many causes, however, may produce a change in this shade, leaving the urine still normal. As can be readily seen the color is closely dependent on concen- tration and must, therefore, vary with the amount of liquid taken into the stomach.

Certain foods from the vegetable kingdom possess characteristic coloring-matters which pass, more or less changed, into the urine. As long as the latter is acid the presence of these may not be noticed, but with a change of reaction a change of color may follow, usually to reddish.

Santonin imparts a yellowish color to urine, red- dened by alkalies. In pathological conditions the color of urine is often characteristic and of great im- portance in diagnosis. The presence of blood, for instance, is indicated by a more or less sharp shade of red, bile by a peculiar greenish brown, especially noticeable in froth produced on shaking. The urine of diabetes mellitus is generally very pale, while the urine of fevers is usually highly colored not only from the diminution of water, but also from the presence of abnormal coloring-matters. Different shades are pro- du