Bacterial superinfection occurs at this

stage.

Heart Disease

In certain types of heart disease, the sputum has

characteristic findings.

In acute edema, the sputum is abundant, frothy and pink

(up to 1 liter may be brought out in a day). Microscopically,

it shows numerous RBCs and large hyaline masses (protein

in nature). In mitral heart disease, the sputum is tenacious

and blood is present, either in streaks or in dark masses

mixed with mucus.

In chronic congestive heart failure, the sputum is frothy

and rust colored. Microscopy reveals the presence of RBCs

and heart failure cells. In fresh unstained sputum, these

cells appear as round colorless bodies filled with various

sized granules of yellow to brown pigment. This pigment

(hemosiderin) can be demonstrated by staining with 10%

potassium ferrocyanide for a few minutes and then with

0.1 N HCl. Hemosiderin pigment stains a blue color.

Viral Infections

Viruses are responsible for 70% to 90% of all respiratory

infections. Preparation of sputum specimens for viral

examination is similar to sputum cytology for malignant

cells. Instead of examining for malignant changes in cells,

the presence of inclusion bodies is looked for.

The inclusion bodies of herpes simplex and adenovirus

are intranuclear. Herpes simplex is easier to identify and

the changes are seen in the young columnar or squamous

exfoliated cells. These mononuclear cells along with giant

cells develop intranuclear eosinophilic inclusion bodies

surrounded by a halo.

Eosinophilic intracytoplasmic inclusions are seen

in parainfluenza and measles virus infections, while

basophilic intracytoplasmic inclusions are present in

respiratory syncytial and cytomegalic viral infections.

Pulmonary Alveolar Proteinosis

Lung biopsy is confirmatory but microscopic examination

of the sputum shows an increase of hypertrophic,

hyperplastic alveolar cells with a granular protein deposit

in the background.

Cytologic Examination in Malignancy

Cytologic sputum examination forms an extremely

important diagnostic test and gives a 50% yield in positive

cases. The most ideal specimen is the single, early

morning, ‘deep cough’ sputum and should be collected

on 3 or 5 consecutive mornings. The samples (unfixed)

should be submitted to the laboratory fresh. Examine the

fresh specimen and select the tissue flecks and bloody

areas for smearing onto a clean slide. The accepted

criterion for a satisfactory sputum sample is the presence

of alveolar macrophages. Four slides are prepared for

examination and stained with the Papanicolaou stain.

If multiple sputum collections are impractical, the most

reliable sample then is the postbronchoscopy sputum

specimen.

Central bronchogenic carcinoma gives the highest

percentage positive results in sputum examination,

although peripheral carcinomas and metastatic carcinomas

may sometimes yield positive results.

15

Pregnancy Tests

C H A P T E R

Pregnancy test is a misnomer as most of the methods

employed measure human chorionic gonadotropin

(hCG) and not the presence of fetus. hCG is a glycoprotein

produced by trophoblastic cells beginning about 10

days after conception. hCG is a dimer—the subunits are

nonspecific (shared with LH, FSH and TSH), the β subunits

are unique to hCG.

Five weeks after last menstrual period (LMP), hCG

begins to rise rapidly in urine and attains peak levels at 10

weeks of gestation.

For laboratory confirmation of early pregnancy, hCG

is the most logical measurement (for evaluation of fetal

distress during the third trimester, estriol is more useful).

BIOASSAYS

Historical Aspects

Aschheium and Zondek Test (1928)

Over a 2-day period give multiple injections of urine to

5 immature female mice about 1 day old, weighing 5 to

7 g each. Sacrifice all animals 4 days after the first injection.

Examine their ovaries for corpus luteum formation. This

test is reliable but too long and time consuming for general

clinical use.

Friedman Test (1931)

A mature female rabbit is injected intravenously with urine;

at 48 hours the ovaries are examined for corpora lutea and

hemorrhagic follicles (The rabbits used should be isolated

for 30 days before use to avoid false positive results).

Bellerby Test (1934)

Female South African clawed toads, Xenopus laevis,

deposit eggs within 24 hours following injection with hCG.

Since,