Lithium-Heparin Plasma Separator Tube (PST), Serum Separator Tube (SST)
Lithium/Sodium-Heparin Green Top Tube (GTT), Red Top Tube (RTT), Grey Top Tube (GYTT)
Cystic fibrosis related diabetes (CFRD) is most common morbidity in patients with cystic fibrosis (CF). Though it shares the features of type 1 and type 2 diabetes, CFRD is distinct clinical entity. Primarily caused by insulin insufficiency as well as fluctuating levels of insulin resistance related to acute & chronic illness also plays a role. Presence of CFRD has negative impact on pulmonary function and survival in CF. The majority of patients with CFRD do not have fasting hyperglycemia, thus in the absence of classic symptoms, the diagnosis of CFRD frequently relies on the oral glucose tolerance test (OGTT). The OGTT is the screening test of choice for CFRD. Although it is an imperfect test due to inherent variability observed in individuals over time, longitudinal studies demonstrate that a diabetes diagnosis by OGTT correlates with clinically important CF outcome including the rate of lung function decline over next 4 years, risk of microvascular complications and risk of early death. As of 2010 annual screening for CFRD starting at age of 10 years is recommended by US Cystic Fibrosis Foundation (CFF) & International Society of Pediatric & Adolescent Diabetes (ISPAD) & American Diabetes Association (ADA) using 2 hour 75 g OGTT (ADA consensus). OGTT should also be performed prior to transplant and pregnancy. (Clinical Care Guidelines for CFRD, Diabetes Care. 2010; 33(12): 2697, J Cystic Fibrosis. 2013; 12: 318). Diagnosis recommendations: During a period of stable baseline health the diagnosis of CFRD can be made in CF patients according to standard ADA criteria. Testing should be done on 2 separate days to rule out laboratory error unless there are unequivocal symptoms of hyperglycemia (polyuria and polydipsia). Positive fasting plasma glucose (FPG) or HbA1C can be used as a confirmatory test, but if FPG is normal the OGTT should be performed. If diagnosis of diabetes is not confirmed, the patient resumes routine annual testing. • 2-h OGTT plasma glucose ≥200 mg/dl • FPG ≥126 mg/dl • A1C >6.5% (A1C >6.5% does not rule out CFRD because this value is often spuriously low in CF.) • Classical symptoms of diabetes (polyuria and polydipsia) in the presence of a casual glucose level >200 mg/dl.