Hospital Corpsman 3 & 2: June 1989
Naval Education and Training Command
A basic knowledge of clinical laboratory procedures is required of all hospital corpsmen, particularly those working at small dispensaries and isolated duty stations without the supervision of a medical officer. The patient's complaint may be of little value by itself, but coupled with the findings of a few easily completed laboratory studies, a diagnosis can usually be surmised and treatment initiated.
Hospital corpsmen who can perform blood and urine tests and interpret the results are better equipped to determine the cause of illness or to request assistance, since they can give a more complete clinical picture. Consequently, their patients can get treated sooner.
In this chapter we will discuss blood collection, the microscope, and step-by-step procedures for the complete blood count and basic urinalysis.
The two principal methods of obtaining blood samples are finger puncture and venipuncture. Both methods have their advantages and disadvantages, but for most clinical examinations, blood is best obtained from a vein.
The finger puncture is used when a patient is burned severely or is bandaged so that the veins are either covered or inaccessible. It is also used when only a small amount of blood is needed.
Equipment Required
Arrange your equipment in an orderly manner and have it within easy reach. As with many other laboratory procedures, wash your hands prior to the procedure.
Procedure
When dealing with infants and very small children, the heel or great toe puncture is the best method to obtain a blood specimen. It is performed in much the same way.
Venipuncture (Vacutainer Method)
The collection of blood from a vein is called venipuncture. For the convenience of technician and patient, arm veins are best for obtaining a blood sample. If arm veins cannot be used due to bandages, IV fluid therapy, thrombosed or hardened veins, etc., consult your supervisor for instructions on the use of hand or foot veins. DO NOT DRAW BLOOD FROM AN ARM WITH IV FLUID RUNNING INTO IT. CHOOSE ANOTHER SITE. THE FLUID ALTERS TEST RESULTS.
Equipment required
Position the patient so that the vein is easily accessible and you are able to perform the venipuncture in a comfortable position. Always have the patient either lying in bed or sitting in a chair with the arm propped up. NEVER PERFORM A VENIPUNCTURE WITH THE PATIENT STANDING UP, AND USE CAUTION TO ENSURE THE PATIENT DOES NOT FALL FORWARD FROM HIS OR HER SEAT.
Procedure
Before any attempts are made to view blood smears, urinary sediments, bacteria, parasites, etc., it is absolutely essential that the beginner know the instrument with which he or she will be spending considerable time-the microscope (fig. 6-3). The microscope is a precision instrument used repeatedly in many areas of the medical laboratory to make visible those objects that are too small to be seen by the unaided eye. This is accomplished by means of a system of lenses of sufficient magnification and resolving power (ability to show, separate, and distinguish) so that small elements lying close together in a specimen appear larger and distinctly separated. Most laboratories are equipped with binocular (two-eye-piece) microscopes, but monocular microscopes are also commonly used. The microscope most often used in the laboratory is a compound microscope that consists of the various pieces identified and discussed briefly below:
Framework:
Base-structure on which the microscope rests.
Arm-structure that supports the magnification and adjustment system; it is the handle by which the microscope is carried.
Stage-platform on which a preparation is placed for examination. In the center of the stage is the aperture or hole to allow passage of light from the condenser. Mechanical stage-means by which the preparation may be moved about on the stage.
Illumination System:
Mirror-usually double, a flat surface on one side, and a concave surface on the other side. The concave surface is used in the absence of a condenser. Many microscopes have a built-in light source instead of a lamp and mirror. Internal light source-built into the base of the microscope, and provides a more precise steady source of light into the microscope.
Condenser-composed of a compact lens system located between the mirror and stage. The condenser (usually an Abbe condenser) concentrates (condenses) the light through the aperture in the stage to the objective lens.
Iris diaphragm-controls the amount of light reaching the condenser. The size of the iris diaphragm opening should approximate that of the face of the objective lens. Thus, as a general rule, the diaphragm is completely closed when liquid.preparations are observed with the low-power objective, and wide open when stained preparations are observed with the oil-immersion lens using natural light.
Magnification System:
Revolving nosepiece-contains openings into which objective lenses may be fitted and that may be revolved to bring an objective into the desired position.
Objective lenses-usually a set of three consisting of a low-power lens (approximate focus 16 mm, magnification 10X), a highpower lens (approximate focus 4 mm, magnification 45X), and an oil-immersion lens (approximate focus 1.8 mm, magnification 100X). Numerical aperture (NA) refers to the angle of the maximum cone of light that may enter the objective. The greater the numerical aperture, the greater the resolution, or ability of the microscope to separate small details clearly.
The body tube-through which light passes from the objective to the ocular lens. The ocular lenses (eyepieces)-usually a 10X is provided: the number indicates the magnification (in diameters) produces by the ocular of the image formed by the objectives. Magnification is determined by the ratio between the size of the virtual image and the real size of the object. It is expressed in diameter multiples, for example 100X. By multiplying the magnification engraved on the objective by that engraved on the eyepiece, one can determine the total magnification. The total magnification resulting from the systems of lenses is determined by the combination of objectives and oculars:
|
Objective lens |
Color Code |
l0X Ocular |
Total Magnification |
|---|---|---|---|
|
16 mm-l0X |
green |
l0x |
lOOX |
|
4 mm-45X |
yellow |
l0x |
450X |
|
1.8 mm-100X |
red |
l0X |
1OOOX |
Composed of two parts, both of which raise or lower the body tube together with the lens system.
Coarse adjustment-the larger and innermost knob; by rotating the control knob, the image appears and is in approximate focus.
Fine adjustment-the smaller and outermost knob; by rotating this control knob, it renders the image clear and well-defined.
The process of focusing consists of adjusting the relations between the optical system of the microscope and the object to be examined so that a clear image of the object is obtained. The distance between the upper surface of a glass slide on the microscope stage and the faces of the objective lens varies according to which of the three objectives is in focusing position. Thus, the intervening distance with the low-power objective (l0X) is the greatest (16 mm), that for the oil-immersion lens (l00X) is the smallest (1.8 mm), and that for the high-power objective (45X) is intermediate (4 mm). As a result, the focusing operation must be conducted with skill to avoid damage to the objective lens, the specimen, or both. It is good practice to obtain a focus with the low-power objective first, then change to the higher objective required. Most modern microscopes are equipped with parfocal objectives, which means that if one objective is in focus, the others will be in approximate focus when the nosepiece is revolved. With the low-power objective in focusing position, observe the following steps in focusing.
The microscope is an expensive and delicate instrument that should be given proper care.
Moving or transporting the microscope should be done by grasping the arm of the scope in one hand and supporting the weight of the scope with the other hand. Avoid sudden jolts and jars.
Make sure the microscope is kept clean at all times; when not in use, enclose it in a dustproof cover or store in its case. Remove dust with a camel hair brush. Lenses may be wiped carefully with lens tissue.
When the oil immersion lens is not being used, remove the oil with lens tissue. Use oil solvents, such as xylol, on lenses only when required to remove dried oil and only in the minimal amount necessary. Never use alcohol or similar solvent to clean lenses.
The complete blood count consists of:
The red blood cell count is made to determine the number of red cells in one cubic millimeter (mm3) of blood. The normal red blood cell count is as follows:
A lower count is usually a sign of anemia.
A lower count is usually a sign of anemia.
Manual Sahli Pipette Method
The materials listed below are required to perform a red blood cell count using the manual Sahli pipette method:
Some common sources of error are:
The Uniopette disposable diluting pipette system for the red blood cell count provides a convenient, precise, and accurate method for obtaining a red blood cell count. The disposable kit consists of a shielded capillary pipette (10 microliter (ul) capacity) and a plastic reservoir containing a premeasured volume of diluent (1:200 dilution).
Procedure
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Example: |
The number of cell in the 5 counting squares was 423. |
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The cell count |
= |
423 x 10,000 |
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|
= |
4,230,000 |
Of the many methods of hemoglobin estimation, the most accurate is reading of hemoglobin as oxyhemoglobin in the photometer, after dilution of the blood with a weak alkali. The Haden-Hausse, Sahli-Hellige, and Newcomer tests, based on acid hematin formed by the action of hydrochloric acid on hemoglobin, are sufficiently accurate for routine examination, provided they are properly done. Since relatively few ships and stations are equipped with a photometer, we will discuss the Sahli-Hellige method.
Materials Required for Sahli-Hellige Test
Reporting. Findings are reported both in grams per 100 ml of whole blood and in percentages of normal values. There are a number of modifications of the Sahli-Hellige method, and 100 percent may be equal to from 13.8 g to 17.3 g. In the sets usually used in the Navy, however, 100 percent is equal to 14.5 g of hemoglobin per 100 ml of whole blood. After reading the percentage on the scale, turn the tube and read from the other side to get the equivalent reading in grams.
If either scale is hard to read, remember that 100% / 14.5 g = 6.9, so one gram of hemoglobin is equal to 6.9 percent. If only one scale can be read, the other reading can be computed.
Caution: Equipment must be clean and dry before determination is started. Wipe all blood from the outside of the pipette before you insert it into the tube. Twenty cubic millimeters is a small volume, and a few blood cells clinging to the outside of the pipette can cause a significant error in findings.
Hematocrit (Packed Cell Volume) Determination
Hematocrit is the volume of erythrocytes expressed as a percentage of the volume of whole blood in a sample. The venous hematocrit agrees closely with the hematocrit obtained from a skin puncture; both are greater than the total body hematocrit. Dried heparin, balanced oxalate, or EDTA is satisfactory as an anticoagulant.
Although the microhematocrit method is not available at all duty stations, it is the most accurate means of determining blood volume and should be used whenever feasible. This test is rapidly replacing the red cell count for general purposes since it is easier, quicker, and more accurate. The method described here is the microhematocrit method.
Normal Values. The normal hematocrit for males is 42 to 50 percent, for females, 40 to 48 percent. A value below an individual's normal range for sex and age indicates anemia.
Materials Required
White Blood Cell (Leukocyte) Count
The total white cell count determines the number of white cells per cubic millimeter of blood. A great deal of information can be derived from white cell studies. The white cell count and the differential count are common laboratory tests and almost a necessity in determining the nature and severity of systemic infections.
Normal Values. The normal range is 4,000 to 11,000 cells per cubic millimeter of whole blood.
Abnormal White Blood Cell Count
The materials listed below are required to perform a white blood cell count using the manual Sahli pipette method:
|
Glacial acetic acid |
2 ml |
|
1 percent aqueous solution of gentian violet |
1 ml |
|
Distilled water |
97 ml |
The gentian violet is not necessary, but by staining the nucleus, it makes the cells more refractile and helps to make an accurate count.
The Uniopette disposable kit for doing a white blood cell count consists of a shielded capillary pipette (20 ul capacity) and a plastic reservoir containing a premeasured volume of diluent (1:100 dilution).
Procedure
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Example: The number of cells in 9 large squares was 90. |
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The cell count |
= |
[90 + (0.1 x 90)] x 100 |
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|
= |
[90 + 9] x 100 |
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|
= |
99 X 100 = 9900 |
Differential White Blood Cell Count
The total white cell count is not necessarily indicative of the severity of a disease, since some serious ailments may show a low white cell count. However, the percentage distribution of the different types of leukocytes in the blood often provides more helpful information in determining the severity and extent of the infection than any other single procedure used in the examination of the blood. The differential count gives these percentages.
Normal Values. The normal percentages of the different leukocytes are:
|
Eosinophils |
(Eos) |
2-4 percent |
|
Basophils |
(Basos) |
0-2 percent |
|
Lymphocytes |
(Lymphs) |
21-35 percent |
|
Monocytes |
(Monos) |
4-8 percent |
|
Neutrophils |
(Neuts) |
|
|
Metamyelocytes |
(Metas) |
0 percent |
|
Bands or Stab forms |
(Bands) |
0-10 percent |
|
Segmented |
(Segs or Polys) |
51-67 percent |
Most hospital corpsmen have heard the expression "shift to the left" and "shift to the right." These terms are often loosely used in refer best be explained by the following diagram:
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Percentage Distribution of the Different Leukocytes | ||||||
|---|---|---|---|---|---|---|
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EOS |
BASOS |
METAS |
BANDS |
SEGS |
LYMPHS |
MONOS |
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Normal Percent | ||||||
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2-4 |
0-2 |
0 |
0-10 |
51-67 |
21-35 |
4-8 |
The metamyelocytes, bands, and segmented neutrophils constitute the neutrophilic cells. When the cells to the left of the segs are increases, it is a "shift to the left." If the segmented neutrophils increase, it is a "shift to the right." The true "right shift" will show numerous hypersegmented (having six or more lobes) neutrophils.
General Interpretations of Leukocytic Changes
The severity of an infection may be determined by the total white cell count and the differential count.
Staining times will vary with different batches of Wright's stain. One batch may give best results with 3 minutes of staining and 2 minutes of buffering, another may give better results with 2 minutes of staining and 3 minutes of buffering. The only way to determine the best time interval for a particular stain is by experimentation.
Next to incorrect time intervals, the most common cause of poor results with Wright's stain is incorrect pH of the staining fluid. If the stain is too acid, the red cells in the smear will stain a bright pink or may even be colorless, while an alkaline stain will cause the red cells to appear blue-gray, with poor color definition. In either case, the pH of the buffering solution should be checked.
Technique for Differential Count
Patient has a white count of 8,000.
Differential count shows 20 percent lymphocytes.
20 percent x 8,000 = 1,600
The patient has 1,600 lymphocytes per cubic millimeter of blood.
The ability to identify the different types of white cells is not difficult to develop, but it does require a thorough knowledge of staining characteristics and morphology that can be gained only by extensive, supervised practice. The beginner is likely to encounter some difficulty in learning to differentiate between monocytes and large lymphocytes, or between monocytes and atypical (not typical) lymphocytes. It is possible also to confuse eosinophils with basophils, since an alkaline stain may cause the orange granules in an eosinophil to appear deep blue or purple. If this happens, the reddish cast in the granules can often be detected by judicious use of the minor focusing knob. Also, the granulations of an eosinophil are generally much finer than those of a basophil, and they tend to concentrate in the cytoplasm.
The neutrophils are subclassified according to age, and the age is indicated by the nucleus. If there is any doubt as to the identity of the neutrophil, always classify it with the older stage. For instance, if a single irregularity in a horseshoe-shaped nucleus appears as a break or a concentration of color, classify it as a segmented neutrophil, not as a neutrophilic band. Practice is the key. And remember-even experienced technicians often disagree as to the identity of a particular cell.
If it is desirable to save a smear for reexamination, remove the immersion oil by placing a piece of lens tissue over the slide and moistening the tissue with xylol. Draw the damp tissue across the slide and dry the smear with another piece of lens paper.
A good smear (thin and evenly distributed) is essential for accurate identification and counting.
The cytoplasm of an eosinophil contains numerous coarse, reddish-orange granules, which are lighter colored than the nucleus.
Scattered large, dark-blue granules, which are darker than the nucleus, characterize the cell as a basophil. Granules may overlay the nucleus as well as the cytoplasm.
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 may be oval, horseshoe- or S- shaped, or segmented (lobulated). The neutrophil is further subclassified according to age as:
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.
Random Specimen
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.
First Morning Specimen
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.
Twenty-four Hour Specimen
This specimen measures the exact output of a specific substance over a 24-hour period. To collect this specimen:
To delay decomposition, use
Other common preservatives are formaldehyde, boric acid, hydrochloric acid, and chloroform. The preservative used must be identified on the label of the container. If no preservative is used, it should be so stated.
Volume (For 24-Hour Specimen or When Requested)
The normal daily urine volume for adults ranges from 800 to 2000 ml, averaging about 1,500 ml. The amount of urine excreted in 24 hours varies with fluid intake and the amount of water lost through perspiration, respiration, and bowel activity. Diarrhea or profuse sweating will reduce urinary output; a high protein diet tends to increase it. Daytime urine output is normally two to four times greater than nighttime output.
Color
The normal color of urine varies from straw to light amber. Diluted urines are generally pale; concentrated urines tend to be darker. The terms used to describe the color of urine are:
The color of urine may be changed by the presence of blood, drugs, or diagnostic dyes. Examples are:
Urine may be reported as clear, hazy, slightly cloudy, cloudy, or very cloudy. Some physicians prefer the term "turbidity" to "transparency," but both terms are acceptable.
Freshly passed urine is usually clear or transparent. In certain conditions it may be cloudy due to the presence of blood, phosphates, crystals, pus, bacteria, etc. A report of transparency is of value only if the specimen is fresh. After standing, all urine becomes cloudy due to decomposition, salts, and the action of bacteria. Upon standing and cooling, all urine specimens will develop a faint cloud composed of mucus, leukocytes, and epithelial cells. This cloud settles to the bottom and is of no significance.
Reaction
Normal urine is slightly acid but will become more alkaline upon standing. The pH ranges from 4.6 to 8.0. The acidity of urine is influenced by many factors, such as a diet high in protein or fat, fasting and starvation, and acid therapy. Alkaline urine may be produced by cystitis, pyelonephritis, and sulfonamide therapy.
It is essential that an alkaline urine be maintained during treatment with sulfonamides, since these compounds are precipitated as crystals in acid solution. The crystals will cause damage to the uriniferous tubules. Sodium bicarbonate is generally used as an alkalizer.
Reaction to pH, protein, glucose, ketones, bilirubin, blood, nitrite, and urobilinogen in urine may be determined by the use of the Multistix and Color Chart. This is a specially prepared multitest strip that is simply dipped into the urine specimen and then compared with the color values for the various tests on the accompanying chart. The color chart indicates pH values, and the numerical value should be reported.
Specific Gravity
The specific gravity of the specimen is the weight of the specimen as compared to an equal volume of distilled water. The specific gravity varies directly with the amount of solids dissolved in the urine and normally is from 1.015 to 1.030 during a 24-hour period.
The first morning specimen of urine is more concentrated and will have a higher specific gravity than a specimen passed during the day. A high fluid intake may reduce the specific gravity to below 1.010. In disease the specific gravity of a 24-hour specimen may vary from as low as 1.001 to as high as 1.060.
The specific gravity may be measured with the urinometer or the index refractometer, available as standard equipment at most duty stations. The refractometer may be held manually (fig. 6-11) or mounted on a stand like a microscope. The specific gravity is determined by the index of light refraction through solid material.
Measurement with Urinometer
Glucosuria is the presence of an abnormal amount of glucose in the urine. Traces of sugar are often found in normal urine, but are not enough to react to any of the routine tests for glucose. However, different sugars in the urine are of various clinical significance. When performing routine urinalysis, we can test for glucose, and any trace of glucose in the test suggests that something is wrong with the patient's carbohydrate metabolism.
Methods for Measuring Glucose
This is the presence of albumin in the urine. Albumin is a protein, consisting of serum albumin and serum globulin that has been eliminated from the blood plasma. It contains carbon, hydrogen, nitrogen, oxygen, and sulfur. Its exact composition has not been determined.
Urinary albumin does not necessarily indicate diseased kidneys; it may reflect reactions to toxic and nontoxic substances originating within the body. Albuminuria is frequently found in young men who have no other signs of disease. This condition is usually transitory. However, albuminuria usually is of clinical significance and generally requires further examination.
Methods for Measuring Albumin in Urine
The test is accomplished by means of test strips. Since practically all urine is tested for both glucose and albumin, the tests are combined in the multitest strips. If the strips are unavailable, or positive for albumin, the sulfosalicylic acid method of albumin determination may be used.
Sulfosalicylic Acid Method of Albumin Determination
CAUTION: The centrifuge is a carefully balanced machine, and efforts should be made to maintain that balance. Specimens should be placed directly opposite each other in the machine. If only one urine specimen is being centrifuged, place a tube containing an equivalent weight of water directly opposite the urine.
Microscopic Examination of Urine Sediment
Usually performed in addition to routine procedures, this examination requires a degree of skill that can be acquired only through practice under the immediate supervision of a competent technician. The specimen should be as fresh as possible, since red cells and many formed solids tend to disintegrate upon standing, particularly if the specimen is warm or alkaline.
Procedure
Leukocytes - Normally, 0 to 3 leukocytes per high-power field will be seen on microscopic examination. More than 3 cells per high-power field probably indicates disease somewhere in the urinary tract. Estimate the number of leukocytes present per high-power field and report it as the "estimated number per high-power field."
Erythrocytes - These cells are not usually present in normal urines. If erythrocytes are found, estimate their number per high-power field and report it. Erythrocytes may be differentiated from white cells in several ways:
Casts - These urinary sediments are formed by coagulation of albuminous material in the kidney tubules. They are cylindrical and vary in diameter depending on the size of the renal tubule or duct of their origin. The sides are parallel, and the ends are usually rounded. Casts in the urine always indicate some form of kidney disorder and should always be reported. If casts are present in large numbers, the urine is almost sure to be positive for albumin. Casts containing organized structures are:
Types of casts:
Cylindroids - Resemble hyaline casts but are more slender and have a slender tail that is often twisted or curled. They frequently are seen along with hyaline casts and have the same significance.
Other microscopic structures found in urine are:
These are not generally pathologic unless present in very large numbers. Certain types of crystals are pathologic; therefore, all crystals seen should be reported.
The Hospital Corpsman and Clinical Laboratory Techniques
As mentioned in the beginning of this chapter, hospital corpsmen are required to have a basic knowledge of laboratory procedures. It is not expected that all hospital corpsmen be proficient in all phases of this field, but it is essential that they know how to perform the tests mentioned in this chapter, since they are eligible for duty independent of a medical officer.
The hospital corpsman is not expected to make diagnoses from test findings or to institute definitive treatment based upon them; however, with the availability of modern communications facilities, the results of these tests will greatly assist him or her in giving a clearer clinical picture to the supporting medical officer.
Needless to say, accuracy, neatness, and attention to detail are essential to obtain optimum test results. Remember also that these tests are only aids to diagnosis-many other clinical factors must be taken into consideration before treatment can be started.
Administrative Responsibilities in the Laboratory
The ability to perform clinical laboratory tests is a commendable attribute of the hospital corpsman. However, the entire effort can come to naught if proper recording and filing practices are ignored and the test results go astray.
Since the test results are a part of the patient's clinical picture, their accuracy and veracity are vital. Since they have a bearing upon the immediate and future medical history, they are made part of the medical record. Erroneous and inaccurate laboratory results have been known to cause extensive embarrassment and medical complications.
As a hospital corpsman, it is your responsibility to assure effective administration of all laboratory reports in your department and to make sure that they are properly filed.
Patient Identification
When accepting laboratory requests and specimens, make absolutely certain that the patient is adequately identified. Proper identification can prevent a great number of errors.
Specimen Identification
Make sure that the specimen is in fact that of the patient submitting it. You need not stand over the patient while it is being collected; however, keep in mind that there are instances when it would be advantageous for persons to substitute specimens.
Use of Proper Forms
The Armed Forces have gone to great lengths to produce workable and effective laboratory forms to serve their purpose with a minimum of confusion and chance for error. These forms are standard forms of the 500 series. Their primary purpose is to request, report on, and record clinical laboratory tests. With the exception of the SF-545, Laboratory Report Sheet, they are multicopy, precarbonized for convenience. The original eventually is filed in the patient's clinical record, and the carbon becomes part of the laboratory's master file. For a complete listing of these forms and their purposes, refer to chapter 23 of the Manual of the Medical Department.
Use of Laboratory Forms
It goes without saying that a separate form is used for each patient and test. The patient's name, rank, Social Security number, and unit identification will be entered on each request in sufficient detail to assure proper identification.
Since the results of the requested laboratory test are usually closely associated with the patient's health and treatment, the requesting physician's name and location shall be clearly stated. This assures that the report will get back to the physician as expeditiously as possible. There is nothing more aggravating to both patient and physician than a lost or misplaced laboratory report.
Since the data requested, the date reported, and the time of specimen collection are usually important in support of the clinical picture, these facts should be clearly written on the request in the areas provided for them.
The type of tests requested should be clearly marked to eliminate all misunderstanding.
Filing the Laboratory Requests
After the physician has seen the results of the laboratory tests, the forms must be filed in the clinical record of inpatients. SF-545, Laboratory Report Sheet, is provided for this. The originals of the test forms are to be stapled on this sheet IN CHRONOLOGICAL ORDER and neatly spaced, as directed on the form. Each sheet will accommodate a certain number of laboratory reports. DO NOT OVERCROWD with more reports-use additional sheets if necessary.
The results of the laboratory tests performed on active duty outpatients will be placed on the SF-545 in the health (medical) treatment record.
The nature of laboratory tests and their results must be treated as a confidential matter between the patient, physician, and the performing technician. It is good practice to prevent unauthorized access to these reports, to leave interpretation of the test results to the attending physician, and to refrain from discussing them with the patient.