_In the absence of any symptoms or physical signs of disease_, a reaction should call for regulation of every day life, tending to increase the state of general resistance (improvement of nutrition, etc.) frequently without discontinuance of work.

The occurrence of reaction, _in the presence of slight symptoms or physical signs_, calls, according to individual condition, either for home treatment with or without discontinuance of work, or sanatorium treatment.

14. INDICATIONS FOR THE SUBCUTANEOUS TUBERCULIN TEST:

The following considerations should guide its employment:

1. A thorough study of the history, thorough physical examination, examination of sputum (if any) give sufficient data for a reliable diagnosis in the vast majority of cases.

2. Cases, with uncertain symptoms or inconclusive physical signs, pointing to possible existence of tuberculous infection, may be treated as "suspicious" cases (without resorting to subcutaneous tuberculin test), the treatment consisting of rearrangement of mode of life, diet, work, etc., that would tend to increase of general resistance of the patient. This can and should be done in the vast majority of suspicious cases.

3. The subcutaneous tuberculin test is indicated in cases in which, in the absence of conclusive symptoms or signs, an absolutely positive diagnosis is desired; then the test should be applied, with the consent of the patient, _after all other methods of diagnosis are exhausted_ (thorough study of the case, thorough physical examination, repeated examinations of sputum, etc).

4. The focal reaction (the reaction pointing to the seat of the disease) occurs in about 1/3, or less, of the general reactions following the subcutaneous tuberculin test; this enhances the value of the test in some cases where a focal reaction would clear the diagnosis.

Above all, the subcutaneous tuberculin test should be used rarely, and then only after all other methods of diagnosis were thoroughly applied.

II. CUTANEOUS TUBERCULIN TEST

1. SYNONYMS: Von Pirquet Test or Skin Test

2. APPARATUS AND DILUTIONS NECESSARY:

Inoculation needle of Von Pirquet

Koch's Old Tuberculin (undiluted or dilutions according to method).

A centimeter tape measure (divided to 1/10 cm.) to measure reactions

Ether

Alcohol lamp

Medicine dropper

3. APPLICATION OF TEST:

Inner surface of the forearm; clean the site with ether; place two drops of tuberculin 4 inches apart; stretch the skin and sc.r.a.pe off the epidermis (at a point midway between the two drops of tuberculin) by rotating the Von Pirquet needle between thumb and index finger, with slight pressure on the skin; repeat same through the two drops of tuberculin; let the tuberculin soak in for a few minutes. No dressing is necessary. The middle scarification is the control test. One tuberculin and one control test may suffice. A separate needle should be used for the control test.

After each inoculation, clean the needle of tuberculin and heat the point red hot in the alcohol flame before applying it again.

4. REACTION:

Gradual elevation and reddening of skin around the point of tuberculin inoculation, beginning in 3 hours or later; the reaction (papule) well developed, generally, in 24 hours and most distinct in 48 hours after inoculation.

Size of papule varies from a diameter of 10 millimeters in the average case to 20 mm. occasionally, and 30, rarely (Bandelier and Roepke).

At the end of 48 hours the swelling and redness subside gradually, with the subsequent bluish discoloration of the skin, remaining for various periods of time, and slight peeling of the epidermis. Individual reactions vary in degree of redness, elevation, size, contour of the border, etc. All these points should be observed and recorded.

Time of inspection--24 and 48 hours after inoculation.

Single inspection--best time in 48 hours.

5. CAUSE OF REACTION:

Interaction between inoculated tuberculin and the antibodies (bacteriolysins, according to Wolff-Eisner) present in the skin of a tuberculous individual; interaction results in hyperaemia and exudation (papule).

6. INTERPRETATION OF REACTION:

Occurrence of positive reaction signifies presence of a tuberculous focus somewhere in the body. No indication as to activity or location of the focus.

A negative reaction in adults (especially if repeated) signifies non-existence of tuberculosis (unless great deterioration of health, far advanced process, or tolerance to tuberculin established by tuberculin treatment).

A positive reaction in children under two years of age signifies, generally, active tuberculous process; with the advance of age the determination of active tuberculous processes by means of cutaneous tuberculin test becomes impossible.

III. CONJUNCTIVAL TUBERCULIN TEST

1. SYNONYMS: Eye Test; Ophthalmic Test; Wolff-Eisner's Test; Calmette's Test.

2. APPARATUS AND DILUTIONS NECESSARY:

1 cc. pipette graduated to 1/10 cc.

10 cc. pipette graduated to 1/10 cc.

10 cc. gla.s.s cylinder

Medicine dropper

Koch's Old Tuberculin

1/2% and 1% dilution of Old Tuberculin in .85% sterile normal salt solution.

To make 1% dilution, add .1 cc. Old Tuberculin to 9.9 cc. of diluent.

3. APPLICATION OF TEST:

Patient sitting, with head thrown back

Lower eyelid drawn slightly down and toward the nose--to form a small pouch of the lid;

One drop of 1% or 1/2% instilled in that pouch and the lower lid moved up gently over the eye until the lids meet;

Eye kept closed for one minute or so.

4. REACTION: