DIAGNOSTIC TEST

1)    SWEAT TEST

The sweat test is considered the “gold standard” for the diagnosis of CF. Though many centers may perform sweat test “screenings”, the only acceptable procedure for diagnosis is called quantitative pilocarpine iontophoresis.. There are two sweat test methods approved by the Cystic Fibrosis Foundation ; the Gibson-Cooke procedure and the Wescor Macroduct  Sweat Collection System. Both methods stimulate localized sweating on the forearm or on the thigh using a chemical called pilocarpine. Sweat is then collected on filter paper or gauze (Gibson-Cooke) or in microbore tubing (Macroduct®). The sweat collected is weighed and analyzed for chloride concentration. Results are interpreted as follows:

RESULT :

Chloride Concentration for Infants (birth to 6 months)	Result
0 - 29 mmol/L	Cystic fibrosis is unlikely
30 - 59 mmol/L	Intermediate
≥ 60 mmol/L	Indicative of cystic fibrosis

Chloride Concentration for Infants (older than 6 months) children and adults	Result
0 - 39 mmol/L	Cystic fibrosis is unlikely
40 - 59 mmol/L	Intermediate
≥ 60 mmol/L	Indicative of cystic fibrosis

2)    NEWBORN SCREENING

   Newborn screening is completed on all infants by collecting blood samples, usually from a heelstick, shortly after birth. These blood samples are collected as blood spots that are allowed to dry on a special filter paper. The dried blood spots are then tested for a variety of diseases. Every state performs newborn screening testing for infants, but not all states include a test for CF

Obtaining blood from newborn screening

3)    CFTR MUTATION ANALYSIS

All individuals carry two copies of the CFTR gene, one inherited from the father and one inherited from the mother. To have CF, an individual must have two abnormal copies, or mutations of the CFTR gene. If the individual has only one mutation, he or she will not be affected with CF, but will be a “carrier”. Because carriers have one abnormal CFTR gene, they can pass this gene to their offspring, placing their children at risk for CF.

More than 1,000 CFTR mutations have been identified. In white populations, the most common mutation is called F508del (previously called ∆F508), and occurs in approximately 70 percent of those CF.

Commercially available mutation screening panels detect most cases of CF. The accuracy of the test will depend on how many mutations are tested and the ethnic origin of the patient (see table below). However, because there are so many described mutations and many more that have not been identified, some patients with clinical features of CF may have only one or no CFTR gene mutations identified by mutation analysis.

Type of clases (CFTR) mutation

Detection of Cystic Fibrosis by Mutation Analysis

25 Mutation Test
Ethnic Group	Detection Rate
Caucasian	90%
African American	69%
Hispanic	57%
Ashkenazi Jewish	97%
Other	unknown

4)    PRENATAL SCREENING

5)OTHER TEST

1)    SPUTUM CULTURE

To detect the presence of bacteria Pseudomonas

2)    X-ray test

3)    LUNG FUNCTION TEST

To measure inspiratory,expiratory capacity, respiratory rate, and blood oxygen level