Q: I've read that the guidelines for donating organs are essentially the same as those for donating blood. I'm concerned because I think I had jaundice soon after birth (I am 67). I was told by the Red Cross many years ago that because of this history of jaundice they could use my blood only for plasma, not as whole blood.

I belong to the Living Bank and my driver's license lists me as an organ donor. No medical questions were ever raised in connection with either listing. So my question is: Does jaundice at birth disqualify me as a potential organ donor?

A: Chances are you're still eligible to donate blood and be an organ donor, but the answer depends on what caused your jaundice at birth.

Many babies develop yellow jaundice shortly after birth, a condition most often caused by the newborn's liver not yet working fully. If this was the case with you, you would be eligible to donate.

Another cause of jaundice is hepatitis (liver inflammation) due to a virus infection. Because the virus can lie dormant for years and be transmitted by blood or organ transplants, having had viral hepatitis would exclude you from donating blood or organs. Blood donation centers routinely screen blood donors for evidence of prior viral hepatitis.

In the unlikely event that you had viral hepatitis at birth (having gotten it from your mother during pregnancy), you would not be able to donate. If you're concerned about this, your doctor can test your blood for signs of previous viral hepatitis. However, these tests would only tell whether, not when, you had had this infection.

I'm puzzled by your being told you could donate plasma, but not blood, because the guidelines for being ineligible to donate either are the same. However, you're right that the guidelines for donating organs are the same as for donating blood. The reason you weren't screened by the Living Bank when you joined is that all blood and organ donors are routinely checked for evidence of viral hepatitis, acquired immune deficiency syndrome (AIDS) and other transmissible diseases at the time of donation.

I'm all in favor of people joining the Living Bank if they're interested in being an organ donor. This nonprofit organization keeps a list of donors and helps in distributing needed organs and tissues. They provide information on organ donation including an organ donor card, and may be reached at 800-528-2971. Local transplant centers include Fairfax Hospital (698-3104), Georgetown University (625-2445), George Washington University (676-3830), Howard University (745-1444) and Washington Hospital Center (541-7777).

Georgetown University transplantation counselors say that people interested in being donors should remember:

There's no cost involved in donating organs.

Donation doesn't interfere with funeral arrangements.

The donor is legally dead before any donation takes place.

Most religions support organ donation.

You should make your wishes known to your family to make sure they're carried out.

No matter how old you are or what illnesses you may have, chances are you're still eligible to be an organ or tissue donor.

Q: Why am I so tired all the time? I just don't seem to have any energy, especially right after I get home from work. What can I do to stop being fatigued? (I hope my letter is clear, since English isn't my first language -- sign language is.)

A: First of all, your letter was very understandable -- I didn't have to edit it much at all.

Second, I'll assume you're talking about fatigue, tiredness and lack of energy, rather than sleepiness and a problem staying awake, which would make me think of narcolepsy, a sleep disorder that I discussed some months ago.

Fatigue is a common reason for seeing a doctor. A recent national medical survey ranked fatigue seventh on a list of reasons for office visits, with more than 10 million visits each year.

Despite it being so common, fatigue can be a difficult symptom for your doctor to diagnose. It may represent anything from the first sign of a serious illness to simply being overworked. Without having any other symptoms to go on, I'll make some general comments about this problem.

Studies show that most people who see a doctor because of fatigue are between 15 and 45 years old. Women outnumber men two to one, but this may only reflect the increased number of visits women make in general. Single people outnumber married people, which may have something to do with psychological causes of fatigue.

Nearly half of patients with this problem have a psychologic cause, such as depression, stress or anxiety, or an understandable explanation that just wasn't obvious to them, such as exhaustion from lack of rest or sleep. Physical causes account for about a third of cases, and in about 10 to 20 percent, no cause is found.

Common physical causes include mononucleosis and other viral infections, unsuspected pregnancy, or reactions to too much alcohol, caffeine or certain medications. Many other diseases can start with a feeling of tiredness.

In general, psychologic fatigue is stress related, is worse in the morning, is relieved by physical activity and shows up more as a lack of desire than a lack of ability to do things.

Physical fatigue, on the other hand, is not primarily related to stress, gets worse as the day goes on or with physical activity, and is more an inability to do usual activities than a lack of desire.

Your doctor will take a detailed history to search for clues to your condition, and may order some routine blood tests. It's important to look for sources of physical or emotional stress, because these are common causes. In many instances, your doctor will want to see how you do over a period of time. Unless something points to a serious problem initially, this test of time, together with some conscientious evaluation, will usually shed light on what's going on.

Jay Siwek, a family physician from Georgetown University, practices at the Fort Lincoln Family Medicine Center in Northeast Washington.

Send questions to Consultation, Health Section, The Washington Post, 1150 15th St. NW, Washington, D.C. 20071. Questions cannot be answered individually.