TRIPASS XR تري باس

  in the dessicant pouch. The results of the test must be

correlated with clinical findings

Problem: Delayed Positive Results

Possible causes Solutions

1. Urine/serum sample used for testing is used immediately

after removal from the refrigerator

Bring the urine/serum samples to be tested to room temperature before

commencing the test procedure

Problem: False Negative Results

Possible causes Solutions

1. Urine/serum stored for a long time is used for testing Fresh early morning urine sample is preferable for testing, as it contains

the highest concentration of hCG, however, if testing is not immediate, the

urine specimen may be stored at 2–8°C for up to 72 hours

Similarly, if fresh serum if used as sample is preferable, however, serum

samples may be stored at 2–8°C for up to 24 hours, in case of delay in

testing

2. Inadequate quantity of sample dispensed in the sample

well of the test device

Dispense exactly 2 drops of urine/serum sample in the sample well.

3. In case of dipstick, improper submerging into the urine/

serum specimen

Dip the orange area of the dipstick in the urine/serum specimen submerging

only the orange area.

4. Error in interpreting results For urine samples, read results at the end of 5 minutes and for serum

samples at the end of 15 minutes.

5. The kit containing the test device is exposed to very high

temperatures leading to the deterioration of antibodies

coated on the device/dipstick

The kit should be stored at 4–30°C when not in use

6. Turbid or contaminated samples are used for testing Avoid using contaminated urine/serum samples. Turbid samples should be

centrifuged, allowed to settle and only the clear supernatant should be used

for testing

7. Highly diluted samples or samples of very early

pregnancy used for testing

Highly diluted samples or samples of very early pregnancy may not contain

representative levels of hCG. In such cases, if pregnancy is suspected, the

test should be repeated with first morning urine after 48–72 hours after the

initial test

Problem: Invalid Results

Possible causes Solutions

1. The pouch may be having pinholes or is in a defected

condition due to which the nitrocellulose membrane has

a tendency of loosing its flow properties

Check the condition of the pouch and observe for pinholes in the pouch if

any before performing the test

2. Change in color of the desiccant accompanying the

pouch

A change in color of the desiccant from deep blue to white/pink indicates

absorbance of moisture. In such cases, discard the test device and rerun

the test using a fresh device

Gravicheck®

16

Examination of

Gastrointestinal Contents

C H A P T E R

NORMAL SALIVA—CONSTITUENTS

Constituents

Volume secreted/24 h 1000–1500 mL

pH 6.3 to 6.85

pH in mouth is usually 7.5–8.0

Specific gravity 1.002 to 1.008

Total solids 0.5 g%

Sodium 17.4 (8.7–24) mEq/L

Potassium 14.1 (13–16) mEq/L

GASTRIC JUICE

Constituents

Digestive enzymes/factors

Pepsin and hydrochloric acid (for protein digestion).

Renin for curdling milk, and gastric lipase—a weak

lipolytic ferment.

Normal Gastric Constituents in Infants and Children

The stomach of neonates secretes small amounts of

pepsin, renin, and free acid. Almost 4% of otherwise

normal children have achlorhydria, this percentage

gradually rises with age (30% have achlorhydria at age 60

years and above). During the first year of life, the volume

of the residuum is 2–5 mL (pH = 2.6–3.0). Both these rise to

adult levels at 15–20 years of age.

Abnormal Gastric Constituents

These may include the following:

1. Blood: An important abnormal finding.

2. Food remnants many hours after eating.

3. Large amounts of mucus or bile.

4. Sarcinae, pyogenic bacteria, lactobacilli, yeast cells.

5. Tissue fragments, large amounts of epithelium.

6. Parasites and ova.

7. Organic acids, e.g. lactic acid, seen in absence of

hydrochloric acid.

8. Tubercle bacilli, in pulmonary tuberculosis, by

swallowing of sputum containing Mycobacterium

tuberculosis.

Routine Gastric Juice Examination

Gross Examination

1. Amount: Normal fasting content is 50–100 mL.

2. Color:

a. Blood is red or the color of coffee ground if acid

hematin is formed.

b. Fresh bile is yellow; old bile is green.

c. In stasis, food colors may persist.

3. Odor:

a. Normal is sour or slightly rancid.

b. Fecal in intestinal obstruction.

c. Ammoniacal in uremia.

4. Character: Let stand, note the three layers:

a. Top—Mucus

b. Middle—Opalescent fluid

c. Bottom—Bread-like residue.

5. Reaction: Acidic—normal pH.

6. Rate of secretion:

a. Mean values for basal rate of secretion of acid

 Age (years) mEq/L

 20–49 2.5

 50–59 2.0

 > 60 1.5

426 Concise Book of Medical Laboratory Technology: Methods and Interpretations

b. Mean values for 12 hours nocturnal secretion in

a normal person

 Volume—580 mL

 Free acid—29 mEq/L or 16.85 mEq/12 hours.

Chemical Examination

1. Blood

May be due to one of the causes of hematemesis, or may

be due to trauma of passing a tube. Do guaiac or benzidine

tests.

2. Qualitative Test for Free HCI (Topfer’s Test)

To 5 drops of gastric juice in evaporating dish, add 1 or 2

drops of 0.5% alcoholic solution of dimethylaminoazobenzene (Topfer’s reagent). Cherry-red color occurs with HCl.

3. Titration for Acid

Method

Transfer 5 mL of gastric juice to an evaporating dish add

20 mL water. Add 3 drops of Topfer’s reagent and 3 drops of

phenolphthalein, and titrate with N/10 NaOH until the last

trace of red color disappears. This is the amount of NaOH

needed to neutralize the free HCI—this value multiplied

by 20 equals the mEq/L of free HCl. Carry on titrating until

red color of phenolphthalein reappears. The total number

of mL of NaOH used (in both titrations) multiplied by 20

equals the mEq/L of total acidity.

Comments

In the fasting state, gastric contents ordinarily contain

0–15% HCl. For gastric juice, the maximum concentration

of HCl is about 0.160 or 160 mEq of HCl/L. The free rather

than total acid primarily determines the pH, which

usually varies in fasting contents from 2.0-1.0, and this

pH range corresponds to an HCl normality (normality =

mEq/L/1000) of about 0.05–0.10. If the normality drops to

0.01 or so, the pH may be about 3.0, and it takes very little

amount of food or any other diluent to bring the pH to 7.0.

Lactic Acid (Kelling’s Test)

Seen usually in achlorhydria only. Add 2 drops of 10%

ferric chloride to one test tube full of water, mix and divide

into 2 test tubes. Add 1 mL of gastric juice to one tube and

compare. Lactic acid gives canary yellow color. Much lactic

acid (over 0.1%) suggests gastric carcinoma.

Microscopic Examination

Place one drop of sediment on a slide and coverslip it.

Look for undigested food particles, blood, mucus, bacteria,

tissue fragments, parasites, sarcinae, yeasts. Lactobacilli

are large nonmotile rods, which stain brown with Gram’s

Normal gastric constituents in adults

Constituents Normal residuum Appetite juice (postseeing/smelling/

tasting of food)

Water (%) 99.02 99.45

Total solids (%) 0.98 0.55

Organic solids (%) 0.53 0.41

Inorganic solids (%) 0.45 0.14

Specific gravity 1.006–1.009 1.007

pH 0.9–1.5 0.9–1.5

Total acidity (mEq/L) 10–50 20–100

Free HCI (mEq/L) 0–30 25–50

Chlorides (g%) 0.5–0.6

Total nitrogen (avg: 66 mg%) 51–75

NPN 20–30

Urea nitrogen 1.3–4

Total sulfur 7

Total phosphorus 5 5

Amino acid N 3–9 3–9

Ammonia N } 2–3 2–3

Examination of Gastrointestinal Contents 427

stain and form lactic acid, they occur in stasis in the

absence of HCl.

Exfoliative cytologic preparations of fresh gastric

washings should be used in the search for gastric

neoplasms.

Gastric Test Meals

Procedures

If the test is to be performed in the morning, give nothing

orally after supper the previous night.

Tubeless Gastric Analysis

This test employs azure-A resin as the indicator (Diagnex

Blue Test).

Azure-A carbacrylic resin dissociates in the presence

of acid to yield free azure-A, which is then excreted in

the urine. In the absence of free acid in the stomach, no

azure-A will be released and hence none will appear in the

urine.

The test meal consists of caffeine with sodium benzoate

to stimulate gastric secretion and azure-A resin granules as

the indicator substance. Urine is analyzed for azure-A by a

simple colorimetric method. On getting up in the morning,

urine is micturated and discarded. Nil orally till the

completion of the test. The gastric stimulant, either 500 mg

caffeine sodium benzoate or 50 mg Histalog is taken

with a glass of water or else histamine or Histalog can be

administered subcutaneously. One hour later, patient

urinates and discards the sample. Immediately thereafter, 2 g

of azuresin are ingested with half glass of water. Two hours

later, the patient urinates and saves the entire sample. The

sample is diluted to 300 mL with water and a 10 mL aliquot

is placed in each of 3 test tubes. Two of the tubes serve as

color controls and to each of these approximately 300 mg

of L-ascorbic acid is added. This reduces the azure-A to a

colorless form. The tubes are then placed in a comparator

block containing azure-A standards of 0.3 mg/300 mL and

0.6 mg/300 mL. If the color of the test urine is more intense

than that of 0.6 mg standard, the test is completed and the

patient is presumed to secrete hydrochloric acid. If the

color of the test urine is less than that of 0.6 mg standard, a

drop of solution containing 195 mg CuSO4.5H2O in 100 mL

of 18% HCl (Diagnex blue reagent) is added to each of the

3 urine tubes. All three tubes are placed in a boiling water

bath for 10 minutes. After cooling at room temperature for

2 hours, the color development is again compared to the

standard solutions. The results are reported as less than 0.3

to 0.6 mg, or greater than 0.6 mg.

Interpretation

This is strictly a qualitative test. An excretion of greater than

0.6 mg azure-A in 2 hours is considered to be indicative of

HCl secretion, while values less than 0.3 mg are considered

presumptive evidence of anacidity. Values between 0.3 and

0.6 mg represent borderline secretion.

Basal Gastric Secretion

This represents the response of the stomach to endogenous

stimuli, which are continually present in the interdigestive

or fasting state.

The minimum requirements include the following:

1. The patient must be in the fasting state and free from

the sight or odor of food.

2. All medications influencing gastric secretion must be

withheld for 24 hours.

3. The patient must be removed from environmental

situations evoking untoward psychological reactions,

such as fear, anger,