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BACTEC NAP TB Differentiation Test is a test to differentiate the Mycobacterium tuberculosis complex from other mycobacteria. Principal use is with the BACTEC 460TB System instrument. BACTEC NAP (ρ-nitro-α-acetylamino-β-hydroxy-propiophenone) TB Differentiation Test is recommended for use with BACTEC 12B Medium for rapid differentiation of the TB complex (M. tuberculosis, M. bovis, M. africanum and M. microti) from mycobacteria other than M. tuberculosis (MOTT). This test should be used in conjunction with bacterial morphology on smear and growth characteristics in BACTEC 12B Medium.

BACTEC 12B Medium does not allow observation of colonial morphology, however, the GI output can be characteristic for certain species of mycobacteria. M. tuberculosis and M. bovis exhibit slow growth with a 2 to 3 fold increase in the daily GI output while other mycobacteria (MOTT bacilli) may show daily increases as high as 10 fold. Visually, M. tuberculosis growth in BACTEC 12B Medium displays small specks or clumps with a clear medium. Other mycobacteria grow in very small particles and may give slight turbidity to the medium.

Smears made from a positive vial (GI = 100 or more) may give an indication of the type of mycobacteria growing in the medium. Presence of serpentine cords and clumps is a characteristic of M. tuberculosis (M. bovis and M. kansasii may also form cords). Other mycobacteria have some other characteristic morphology, such as M. avium/M. intracellulare which show branching with long strands of bacilli.

The BACTEC NAP Test further helps in a rapid differentiation of M. tuberculosis, the most important species of mycobacteria. This test is independent of the Niacin test. A sample of actively growing culture is inoculated into the NAP vial which contains a disc containing 5 μg of NAP. The vial, along with the control, is incubated and growth in the presence of NAP is monitored on the BACTEC 460TB System instrument. Analysis of the daily GI readings within the next 3 to 5 days helps in the differentiation of the TB complex from other mycobacteria.

The following positive and negative controls should be included in each batch of testing to ensure the accuracy of the test procedure.

*For details, see the BACTEC 460TB System Product and Procedure Manual (MA-0029).

DO NOT USE vials past their expiration date.

DO NOT USE vials that exhibit any cracks or defects; discard the vial in an appropriate manner.

Quality Control Certificates are provided with each NAP Kit. Quality Control Certificates show test organisms utilized for this type of product.

As part of the daily maintenance schedule, Performance Test Vials (BACTEC Performance Test Kit) should be tested on the BACTEC instrument. If low readings are obtained, yet Performance Test Vials were tested properly, possible instrument problems may be indicated (see the BACTEC PTK package insert, PP-046JAA).

Quality control requirements must be performed in accordance with applicable local, state and/or federal regulations or accreditation requirements and your laboratory's standard Quality Control procedures. It is recommended that the user refer to pertinent NCCLS guidance and CLIA regulations for appropriate Quality Control practices.

The BACTEC NAP Kit vials contain a paper disk with the following active ingredient:

For in vitro Diagnostic Use.

This Product Contains Dry Natural Rubber.

Pathogenic microorganisms, including hepatitis viruses and Human Immunodeficiency Virus, may be present in clinical specimens. "Standard Precautions"^1-4 and institutional guidelines should be followed in handling all items contaminated with blood or other body fluids.

DO NOT USE a NAP Differentiation Test vial if it is obviously contaminated, discolored, or does not contain a disk. Moisture, especially at higher temperatures, causes rapid deterioration of NAP.

Aseptic techniques and established procedures against microbial hazards should be used at all times.⁵ Always use within a biological safety cabinet. Avoid any contact with the disc. After use, specimen containers and other contaminated material should be sterilized by autoclaving.

Prior to use, each vial should be examined for evidence of damage.

Vials that exhibit evidence of damage should be discarded prior to inoculation. On rare occasions, the glass bottle may be cracked and the neck may break during removal of the flip-off cap or in handling. Also on rare occasions a vial may not be sealed sufficiently. In both cases, the contents of the vials may leak or spill, especially if the vial is inverted. If the vial has been inoculated, treat the leak or spill with caution, as pathogenic organisms/agents may be present. Before discarding, sterilize all inoculated vials by autoclaving.

Positive culture vials for subculturing or staining: Before sampling it is necessary to release gas which may build up due to microbial metabolism. Aseptic techniques and established precautions against microbial hazards should be used at all times. Procedures should be performed in a suitable biological safety cabinet in a room with an appropriate ventilation system as recommended by the CDC.⁵ Use a proper protective gown, mask, and gloves while handling specimens and cultures of potential pathogens. Follow the CDC and OSHA recommendations.

To minimize the potential of leakage during inoculation, use syringes with permanently attached needles or securely fastened Luer-Lok brand tips.

The toxicity of this compound has not been studied. Its use should be accompanied by appropriate procedures to avoid exposure.