A delayed hemolytic transfusion reaction (DHTR) is a type of transfusion reaction. According to the Centers for Disease Controls (CDC) National Healthcare Safety Networks (NHSN) Hemovigilance Module, it is defined as:

Mechanism
If a person without a Kidd blood antigen (for example a Jka-Jkb+ patient) receives a Kidd antigen (Jka-antigen for example) in a red blood cell transfusion and forms an alloantibody (anti-Jka); upon subsequent transfusion with Jka-antigen positive red blood cells, the patient may have a delayed hemolytic transfusion reaction as their anti-Jka antibody hemolyzes the transfused Jka-antigen positive red blood cells. Other common blood groups with this reaction are Duffy, Rhesus and Kell. Diagnosis
Positive direct antiglobulin test (DAT) for antibodies developed between 24 hours and 28 days after cessation of transfusion
Positive elution test with alloantibodies present on the transfused red blood cells OR newly identified red blood cell alloantibodies in recipient serum.Antibody elution is the process of removing antibodies from the surface of red blood cells. Techniques include using heat, ultrasound, acids or organic solvents. No single method is best in all situations. In an elution test, the eluted antibodies are subsequently tested against a panel of reagent red blood cells of known phenotype. Inadequate rise of post-transfusion hemoglobin level OR rapid fall in hemoglobin level back to pre-transfusion levels OR otherwise unexplained appearance of spherocytes.PROBABLE DIAGNOSIS

Newly identified red blood cell alloantibody demonstrated between 24 hours and 28 days after cessation of transfusion BUT incomplete laboratory evidence to meet definitive case definition criteria.
Rapid growers include four well-recognized, pathogenic, rapidly growing, nonchromogenic species: M. chelonae, M. abscessus, M. fortuitum, and M. peregrinum. Other examples cause disease rarely, such as M. smegmatis and M. flavescens.The number of identified and cataloged NTM species has been increasing rapidly, from about 50 in 1997 to over 125 by January 2007. The surge is mainly due to improved isolation and identification techniques.Even with these new techniques, though, the Runyon classification is still sometimes used to organize the mycobacteria into categories. Epidemiology
NTM are widely distributed in the environment, particularly in wet soil, marshland, streams, rivers and estuaries. Different species of NTM prefer different types of environment. Human disease is believed to be acquired from environmental exposures. Unlike tuberculosis and leprosy, animal-to-human or human-to-human transmission of NTM rarely occurs.NTM diseases have been seen in most industrialized countries, where incidence rates vary from 1.0 to 1.8 cases per 100,000 persons. Recent studies, including one done in Ontario, Canada, suggest that incidence is much higher. Pulmonary NTM is estimated by some experts in the field to be at least ten times more common than TB in the U.S., with at least 150,000 cases per year. Most NTM disease cases involve the species known as Mycobacterium avium complex or MAC for short, M. abscessus, M. fortuitum and M. kansasii. M. abscessus is being seen with increasing frequency and is particularly difficult to treat.Mayo Clinic researchers found a three-fold increased incidence of cutaneous NTM infection between 1980 and 2009 in a population-based study of residents of Olmsted County, Minnesota.