The calendar is a good prompt. In the UK, the seasons change how much sun reaches your skin, what is floating in the air and where people go on holiday. Some seasonal blood tests follow that rhythm naturally. This guide walks through four moments of the year when a particular test from the BPR catalogue tends to come up, what it measures and how the sample is collected through London Medical Laboratory (LML).
Late winter: vitamin D
The NHS explains that between October and early March we do not make enough vitamin D from sunlight in the UK, and that from about late March or early April to the end of September most people can make what they need from the sun. Government advice, based on the Scientific Advisory Committee on Nutrition report, is that everyone should consider a daily vitamin D supplement in autumn and winter, and that adults and children from one year old need 10 micrograms a day.
Vitamin D helps regulate calcium and phosphate, which keep bones, teeth and muscles healthy. LML notes that up to a quarter of the population is low in vitamin D at the end of winter. That is why the end of winter, around February or March, is when the Vitamin D test is most often discussed: it shows where your level sits after the darkest months.
If you already take a supplement, a test can show where you sit with it. Whether to change anything is a decision for a health professional, not for the result alone.
Before spring: allergy panels
The NHS describes hay fever as a common allergy, with symptoms usually worse between late March and September, when the pollen count is at its highest. It can cause sneezing, a runny or blocked nose, itchy eyes, headache and tiredness, and it can last for weeks or months, unlike a cold.
Allergic rhinitis is caused by IgE-mediated reactions to inhaled allergens such as pollen, and it is one of the most common long-term conditions worldwide (Bousquet et al., 2020). The Allergy Complete test measures IgE against 295 allergens, including pollens, foods and animals, from one blood sample. LML notes it can be done on a finger-prick home sample as well as a phlebotomy sample, and the result takes about five to seven days.
Some people prefer to test in late winter, before the season starts, so they have the result in hand when symptoms usually begin. The same review describes clinical history as the starting point, with blood IgE to specific allergens added when needed, so a result is always read alongside your symptoms by a GP or allergy specialist.
Before summer travel: immunity checks
Holiday plans are a reminder to look at vaccinations. The NHS recommends getting advice from a travel health professional at least 4 to 6 weeks before you travel, because some vaccines need a course of doses and others take time to build protection. Hepatitis A vaccination is free on the NHS for travel, while hepatitis B is among the vaccines you usually pay for.
Two tests in the catalogue measure antibodies to these viruses. The Hepatitis A Immunity (IgG/IgM) test measures antibodies to hepatitis A, and the Hepatitis B Immunity (Quantitative) test measures the hepatitis B surface antibody. A result can be a useful piece of information to bring to a travel health appointment, especially if you are not sure what you had in the past. It does not replace the advice of the travel health professional, who decides which vaccines make sense for your trip.
